Structural Evolution in the Rare-Earth Uranyl Vanadates Ln2[(UO2

Subscriber access provided by EDINBURGH UNIVERSITY LIBRARY | @ http://www.lib.ed.ac.uk

Article

Structural Evolution in the Rare-Earth Uranyl-vanadates Ln2[(UO2)2V2O8]3·nH2O, Singularity of the Lanthanum Compound and Single-crystal-to-single-crystal Partial Dehydration Alexandre Mer, Said Obbade, Philippe Devaux, and Francis Abraham Cryst. Growth Des., Just Accepted Manuscript • DOI: 10.1021/acs.cgd.9b00171 • Publication Date (Web): 18 Apr 2019 Downloaded from http://pubs.acs.org on April 20, 2019

Just Accepted “Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides “Just Accepted” as a service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these “Just Accepted” manuscripts.

is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Published by American Chemical Society. Copyright © American Chemical Society. However, no copyright claim is made to original U.S. Government works, or works produced by employees of any Commonwealth realm Crown government in the course of their duties.

Page 1 of 28 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Crystal Growth & Design

Structural Evolution in the Rare-Earth Uranyl-vanadates Ln2[(UO2)2V2O8]3·nH2O, Singularity of the Lanthanum Compound and Single-Crystal-to-Single-Crystal Partial Dehydration. Alexandre Mer,† Saïd Obbade,‡ Philippe Devaux,† and Francis Abraham† †Université

Lille, CNRS, Centrale Lille, ENSCL, Université Artois, UMR 8181 - UCCS - Unité de Catalyse et Chimie du Solide, F-59000 Lille, France ‡ LEPMI

UMR 5279, Grenoble INP — Université Grenoble Alpes, BP 75, 38402 Saint-Martin d’Hères Cedex,

France

E-mail: [email protected]

KEYWORDS Rare-earth uranyl vanadate, Crystal structure determination, Carnotite group, single-crystalto-single-crystal dehydration

ABSTRACT

A family of compounds with general chemical formula Ln2[(UO2)2V2O8]3·nH2O where Ln = La, Ce, Pr, Nd, Sm, Eu, Gd, Er, Yb and Y has been hydrothermally synthesized and structurally characterized. The structure of all these compounds can be described as the stacking of carnotite-type uranyl-vanadate layers pillared by lanthanide-oxygen polyhedra. Except for La, they are isostructural and the crystal structure determination of Nd2[(UO2)2V2O8]3·22H2O and Y2[(UO2)2V2O8]3·20H2O shows that the ud/du/du geometrical isomer of the uranyl-vanadate layers are pillared by Nd(Oyl)2(H2O)7 and Y(Oyl)2(H2O)6 1

ACS Paragon Plus Environment

Crystal Growth & Design 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 2 of 28

polyhedra, respectively, through interactions between the lanthanide ion and the oxygens Oyl of two vanadyl ions forming V = Oyl – Ln – Oyl = V entities. In the La compound, the ud/du geometrical isomer of the uranyl-vanadate layers are pillared by La(Oyl)2(H2O)8, through interactions between the lanthanum ion and the oxygens Oyl of one vanadyl and one uranyl ions forming U = Oyl – La – Oyl = V entities. Thermogravimetric and high temperature X-ray diffraction studies show that the dehydration of the La compound is also singular, while the dehydration of other compounds involves a regular decrease of the interlayer space, for La it is realized through structural transitions. Upon partial dehydration, the La crystalline material undergoes a single-crystal-to-single-crystal transition between the 20- and 6- hydrates. Despite very large variation of the unit cell parameters and volume COE = -27.8%!), the crystal remained of sufficient quality to allow the crystal structure determination of the hexahydrate. The total dehydration is reversible. INTRODUCTION

Uranyl vanadates are among the most insoluble and most stable uranyl minerals which is one of the reasons why they are so abundant in nature and one of the major ores of uranium The majority of them belong to the carnotite-group.1,2 Carnotite-group minerals have the general formula Mn+2/n(UO2)2V2O8·xH2O, where M is a monovalent cation (K = carnotite, Cs/K = Margaritasite) or a divalent cation (Ca = tyuyamunite and metatyuyaminite, Ba and Ba/Pb = francevillite, Pb = curienite) and their structures consist of [(UO2)2V2O8] 2 sheets built from dimeric units of edge-sharing UO7 pentagonal bipyramids bridged by centrosymmetric dimers of edge-sharing VO5 square pyramids with Mn+ ions and H2O molecules in the interlayer space. Only two mineral uranyl vanadates of the carnotite-group, vanuralite

and

metavanuralite,

have

been

identified

for

a

trivalent

M

cation,

Al(UO2)2V2O8(OH)·nH2O, with n = 11 and 8, respectively; the structure of synthetic

2


Page 3 of 28 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Al(UO2)2V2O8(OH)·8.5H2O has been recently reported.3 The excess charge of aluminium is compensated by an hydroxyl ion as the excess charge of the two copper in sengierite Cu2(UO2)2V2O8(OH)2·6H2O.4 Many other materials pertaining to the carnotite-group have been synthesized where Mn+ is an alkaline metal,5,6,7 NH4+,8 H3O+,9 Ag+,10 an alkaline earth,11,12,13 a divalent transition metal14 or an organic template.15 Although the rare earths are found as impurities in some uraninite ores and as a major component in natural minerals such as the carbonate bijvoetite,16 there are no natural uranyl vanadate mineral containing rare earth so far identified, to our knowledge. However, rare earths constitute an important part of fission products and some of them share sometimes similar physicochemical properties with transuranic elements in trivalent state. This similarity is an asset used to simulate the behavior of minor actinides included in the nuclear wastes for deep underground disposal, which is a critical issue in the management of spent fuel. The alteration products of the nuclear waste in wet and oxidizing conditions are the phases containing the uranyl ion resulting from the oxidation of uranium U4+ to U6+, which can be associated with different oxoanions such as vanadate, and some radionuclides (fission products and actinides). Recently the solid state synthesis and characterization of two lanthanide uranyl-vanadates have been reported: (i) the lanthanum uranyl vanadate divanadate, [La(UO2)V2O7][(UO2)(VO4)] with structure characterized by the stacking of uranophane-type sheets [La(UO2)(V2O7)]+ resulting from the connection of two

2

[(UO2)(VO4)]- and double layers 2

2

[La(UO2)(VO4)2]- sheets derived

from the uranophane anion-topology,17,18 by replacing half of the uranyl ions by lanthanum atoms;19 (ii) the europium uranyl-vanadate Eu2(UO2)2[(UO2)(VO4)]10·14H2O with a 3D structure resulting from the stacking of uranophane-type sheets

2

[(UO2)(VO4)]- pillared by

polyhedra around additional uranyl and europium atoms.9 Previously Uranyl-vanadates with formula A(UVO6)3·nH2O with a layered structure have been prepared for A = Y, La, Ce, Sm, Dy, Lu.20 Recently, the crystal structure determination of the Nd and Eu phases confirms that 3



Page 4 of 28

they belong to the carnotite-group and are potential hosts for immobilization of trivalent lanthanides and actinides.9 In this paper we report the evolution of the crystallographic data along the lanthanide series and the structure of the lanthanum, neodymium and yttrium compounds at 20°C. Despite a large variation of the unit cell during the first dehydration, a single-crystal-to-single-crystal (SCSC) transformation allows determination of the crystal structure of the lanthanum compound at 70°C. The reversible total dehydration-hydration of the lanthanum compound is also reported.

EXPERIMENTAL Caution: Uranium is a radioactive and chemically toxic reagent and uranium-containing samples have to be handled by qualified personnel in appropriate facilities with suitable care and protection.

Synthesis Pure polycrystalline samples of Ln2[(UO2)2V2O8]3.nH2O were obtained by reaction between U2V2O11 prepared as described in21 used as a precursor of uranium and vanadium and lanthanide chlorides LnCl3W 62O (Ln = La, Ce: x = 7, Pr, Nd, Sm, Eu, Gd, Y, Er, Yb: x = 6) mixed in the molar ratio corresponding to Ln/U/V = 1/3/3. For each synthesis, 0.15 mmole (0.1131g) of U2V2O11 were mixed with 0.1 mmole of the lanthanide chloride, the mixture was introduced in a 23 mL Teflon-lined Parr digestion bomb and added with 15mL of distilled water. The whole was heated at 190°C for 4 days then cooled to ambient temperature at 10°C/hr. The resulting products were recovered by filtration, washed with water and finally dried in air at room temperature. In these conditions, for the other lanthanides (Tb, Dy, Ho, Tm, Lu), corresponding compounds were not obtained. Crystals of suitable quality for X-ray diffraction experiments were isolated for Ln = La, Nd and Y. 4


Page 5 of 28 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Powder X-ray diffraction (PXRD). For the determination of unit cell parameters X-ray diffraction patterns were recorded under air over the angular range 5-80° (2 ), with a step length of 0.02° (2 ) and a counting time of 15s.step-1 with a Bruker AXS D8 ADVANCE diffractometer with the parafocusing Bragg–Brentano geometry, using CuK 1, 2 radiation (

K 1

=1.54051 Å,

K 2

=1.54433 Å)

and an energy dispersive detector (sol-X). Unit cell parameters were refined by applying the ‘‘pattern matching’’ option of the FullProf program22 to the whole diagram. The peak shape was fitted by a pseudo-Voigt function. In order to describe the angular dependence of the peak full-width at half-maximum (H), the formula of Caglioti et al.23 was used, where U, V and W are parameters refined in the process. The calculations involved the refinement of .Z zero-point, cell parameters and background level by a polynomial function. The fit of calculated data in regard to the observed data was indicated by the reliability factors and by the plot of observed and calculated patterns represented in SI, Figure 1. High temperature X-ray diffraction (HTXRD) In-situ High Temperature X-ray Diffraction (HTXRD) experiments were performed under dynamic air (5 L.h-1) in an Anton Paar HTK1200N chamber of a Bruker D8 Advance diffractometer (Z[Z mode, Cu K\ radiation) equipped with a Vantec1 linear position sensitive detector (PSD). Several diagrams were recorded in air between ambient temperature and 800 °C every 25 °C, in the range 10-80° C.ZD with a step 0.02° and a heating at 0.8 °C min-1. Single-crystal X-ray diffraction and structure determination Well-shaped yellow crystals of Ln2[(UO2)2V2O8]3WnH2O, Ln = La, Nd, Y were selected for X-ray diffraction investigations. Single-crystal X-ray diffraction data were collected at 20°C on a Bruker X8-APEX2 X-ray diffractometer equipped with a 4K CCD detector and

5



monochromated

MoK

radiation

C]H,:/ ,/3

Page 6 of 28

Å).

A

single

crystal

of

La2[(UO2)2V2O8]3W20H2O was heated using a Cryostream 700 heating device from Oxford Cryosystems and the X-ray diffraction data were collected after the first dehydration at 70°C giving La2[(UO2)2V2O8]3W6H2O. During this dehydration process, the crystal transforms layerwise, without complete delamination or deterioration, and despite of a large variation of the interlayer space (from 9.452 Å to 7.086 Å) and unit cell volume (from 2484.6 Å3 to 1794.6 Å3, OE = -27.8%), the crystal remained of sufficient quality to allow the investigation of the crystal structure by single X-ray diffraction, however no diffraction was observed for .

^K]

> 0.516 Å C^ > 21.50°). Details of the data collection for Ln2[(UO2)2V2O8]3WnH2O, Ln = La, Nd, Y at 20°C and La2[(UO2)2V2O8]3W6H2O at 70°C are given in Table 1. Before the crystal structure determination, the intensity data were corrected for Lorentz, polarization and background effects using Bruker program SAINT.24 Then the absorption corrections were computed by the Gaussian face-indexed method with the shape of the crystal using the program XPREP of the SHELXTL package,25 followed by a semi-empirical correction based on redundancy using the SADABS program.26 The four crystal structures were solved in the centrosymmetric P21/c space group by means of direct methods strategy using SHELXS program25 that localize the heavy atoms U, Ln and V. The positions of the oxygen atoms were deduced from subsequent refinements and difference Fourier syntheses. For the Y compound all the atoms were refined anisotropically. For the Nd and La compounds at ambient temperature, some water oxygen atoms are disordered and refined isotropically. In the study of the structure of the Nd and Eu compounds by Wang et al.,9 the lanthanide atoms are partially disordered, in the present study the rareearth atoms (La, Nd, Y) totally occupy a single crystallographic site, this may be due to

6


Page 7 of 28 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


different synthesis conditions. For the La compound at 70°C, only La, U and V atoms were refined anisotropically. Positions of H atoms of H2O molecules were not localized. Crystal data and structure refinement parameters are reported in Table 1. Table1. Crystal data, intensity collection and structure refinement parameters for Ln2[(UO2)2V2O8]3W20H2O, Ln = Y, La, Nd2[(UO2)2V2O8]3W22H2O, and La2[(UO2)2V2O8]3W6H2O.

La2[(UO2)2V2O8]3 20H2O La2[(UO2)2V2O8]3 6H2O Nd2[(UO2)2V2O8]3 22H2O Y2[(UO2)2V2O8]3 20H2O Formula

O28H20LaV3U3

O21H6LaV3U3

O29H22NdV3U3

O28H20YV3U3

CCDC number

1894960

1894963

1894961

1894962

Formula weight

1473.98

1347.87

1497.32

1423.98

Temperature/K

293

363

293

293

Crystal color

Yellow

Yellow

Yellow

Yellow

Crystal system

Monoclinic

Monoclinic

Monoclinic

Monoclinic

Space group

P21/c

P21/c

P21/c

P21/c

a/Å

9.8269(3)

7.9090(9)

9.6530(6)

9.3464(3)

b/Å

24.8017(6)

24.2830(19)

10.5242(6)

10.5212(3)

c/Å

10.5986(3)

10.4411(15)

26.3024(15)

25.2094(7)

/(0

90

90

90

90

1(0

105.88(2)

116.498(8)

103.30(3)

102.90(10)

2(0

90

90

90

90

Volume/Å3

2484.61(12)

1794.6(4)

2501.5(3)

2416.44(12)

Z

4

4

4

4

4calcg/cm3

3.940

4.989

3.976

3.914

5/mm-1

22.349

30.890

22.571

23.625

F(000)

2584

2304

2636

2512

Radiation

9 range for data collection/° Index ranges

#$ % = 0.71073)

2.58 – 31.51

1.68 – 22.00

2.54 – 25.51

2.54 – 30.51

-14 ) h ) 14

-8 ) h ) 8

-11 ) h ) 11

-13 ) h ) 13

-36 ) k ) 36

-24 ) k ) 24

-12 ) k ) 12

-15 ) k ) 15

-15 ) l ) 15

-10 ) l ) 10

-30 ) l ) 30

-36 ) l ) 36

7



Page 8 of 28

Reflections collected

71978

13502

25513

38598

Independent reflections

8280 [Rint = 0.0343, Rsigma = 0.0565]

2040 [Rint = 0.0869, Rsigma = 0.1237]

4619 [Rint = 0.0435, Rsigma = 0.0581]

Data/restraints/parameters

8280/0/319

2040/0/149

4619/0/324

7361 [Rint = 0.0523, Rsigma = 0.0663] 9816/0/316

Goodness-of-fit on F2 Final R indexes [I>=2@ (I)] Final R indexes [all data] Largest diff. peak/hole / e Å-3

1.013

1.040

1.019

1.053

R1 = 0.0285 wR2 = 0.0604 R1 = 0.0461 wR2 = 0.0665

R1 = 0.0589 wR2 = 0.1309 R1 = 0.0976 wR2 = 0.1517

R1 = 0.0287, wR2 = 0.0676 R1 = 0.0411, wR2 = 0.0613

R1 = 0.0307, wR2 = 0.0707 R1= 0.0529, wR2 = 0.0815

2.67/-1.41

3.41/-2.91

2.42/-1.61

2.19/-1.11

Thermogravimetric (TGA) and Differential Thermal Analyses (DTA) Thermogravimetric and Differential Thermal Analyses were carried out with a SETARAM 92 thermal-1600 instrument at a heating at 1°C.min-1 using platinum crucibles in the range 20-700°C in air. RESULTS AND DISCUSSION Description of the structures of Ln2[(UO2)2V2O8]3·nH2O, Ln = La, Y (n = 20), Nd (n = 22) The structures consist of [(UO2)2V2O8] 2 sheets with the francevillite anion topology (Figure 1 a) using the description developed by Burns et al.17,18 with Ln3+ ions and H2O molecules in the interlayer space. All the pentagons are occupied by uranyl ions, all the squares by vanadyl ions, whereas the triangles are empty. This results in dimeric units of edge-sharing UO7 pentagonal bipyramids further connected by corner sharing to form a 2-D network with large cavities occupied by dimers of edge-sharing VO5 square pyramids. The VO5 pyramids in the V2O8 dimers are related by an inversion center at the middle of the shared edge, so the two vanadyl bonds are on different sides of the layer. A V2O8 dimer can be referenced as ud with a tetragonal pyramid that point up and one down. In P layers observed in carnotite and almost all the monovalent ion containing A2[(UO2)2V2O8]·xH2O

8


Page 9 of 28 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


compounds, the V2O8 dimers alternate, along [0 1 0], to form the isomer ud/du (Figure 1 b). In the lanthanum compound the same isomer is obtained but the b unit cell parameter must be multiplied by three (Figure 1 c) to account for the occupation of sites by lanthanum atoms (Figure 2 b). For Ln = Nd and Y the corresponding parameter is also multiplied by three (Figure 2 c), but this multiplication is the result of a different geometrical isomer of the carnotite sheet with a sequence ud/du/du (Figure 1 d). The geometrical isomer du/du has been formed with 1,4-dimethylpiperazine and 1,2-ethylenediamine as counter cations of the carnotite-type layer.15 In the carnotite and La compounds the successive parallel layers are shifted in the X direction while they are moved in the perpendicular Y direction for other lanthanides leading to an inversion of the b and c parameters (Figure 1).

a) Y

b)

c)

Figure 1. The [(UO2)2V2O8] 2

X

c) d)

layers of a) the francevillite anion topology with b) the ud/du

geometrical isomer in Cs2[(UO2)2V2O8] and c) La2[(UO2)2V2O8]3·20H2O and with d) the

ud/du/du sequence in Y2[(UO2)2V2O8]3·20H2O and Nd2[(UO2)2V2O8]3·22H2O. VO5 square pyramids in orange, U2O7 pentagonal bipyramids in yellow.

9



Page 10 of 28

Cs La Y, Nd

a)

b)

c)c)

Figure 2. Positions occupied by a) Cs atoms in Cs2[(UO2)2V2O8], b) La atoms in La2[(UO2)2V2O8]3·20H2O,

c)

Y

and

Nd

atoms

in

Y2[(UO2)2V2O8]3·20H2O

and

Nd2[(UO2)2V2O8]3·22H2O. For the three studied compounds the U – Oyl (Oyl denotes a uranyl-ion O atom) bond distances range from 1.781(5) to 1.809(5) Å (avg. 1.793 Å). The equatorial U – Oeq bond lengths vary from to 2.290(4) to 2.402(4) Å (avg. 2.346 Å). These values are in agreement with those calculated for 270 UO7 polyhedra in 143 structures by Burns, 1.79(4) and 2.37(9) Å for U – Oyl and U – Oeq, respectively.27 The Oyl – U – Oyl bond angles are between 178.8(2) and 179.6(3)° (avg. 179.1°). The bond-valence sums calculated using the parameters established for UO7 polyhedra (Rij = 2.045 Å, b = 0.510 Å)24 are in the range 6.01 – 6.08 vu. The V – Oyl (Oyl denotes a vanadyl-ion O atom) bond distances range from 1.595(5) to 1.629(5) Å (avg. 1.613 Å), the equatorial V – Oeq bond lengths vary from 1.767(4) to 1.982(4)

10


Page 11 of 28 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Å (avg. 1.863 Å) in agreement with the values found for [1+4] square-pyramidal coordination polyhedra around V5+ ion.28 Rare-earth coordination The oxygens Oyl of the uranyl are not totally inert and are known to form, in condensed phases, and particularly in layered compounds where uranyl bonds point toward the interlayer space, interactions with alkali such as in M2U2O7 diuranates (M = Na,29,30 K,31 Rb,32 Cs,33) alkali earth, transition and post-transition metal in MUO4 uranates (M = Ca, Sr, Ba,34,35 Cu,36 Pb37) and lanthanide19 cations occupying the interlayer space. Such common Uranyl – Oyl – Metal interactions are sometimes abusively called “heterometallic cation-cation interactions”.38,39 In fact cation-cation interactions (CCIs) were first identified for neptunyl and uranyl cations in solution by Sullivan40 and describe the situation where an O atom of an actinyl ion is also an equatorial ligand of a neighbouring actinyl polyhedron, so CCIs are Uranyl – Oyl – Uranyl interactions. Later CCIs were described in solids, CCIs lead to an increase of the dimensionality of the structures, one actinyl ion coordinating one to four other actinyl ions.41 Although rarer than with Np (V),42,43,44,45 several papers report CCIs with U (VI) in inorganic materials such as uranyl oxides,46 uranyl oxide hydrates47,48 uranyl oxychlorides,49 uranyl arsenates,50 uranyl vanadates,51,52 uranyl tungstates,53,54 uranyl periodates,55 uranyl germanates,56 uranyl molybdates,57,58 uranyl sulfate.59,41 Oxygens Oyl of vanadyl ions are not also totally inert and form, in condensed phases, interactions with metal atom such as in some carnotite-type layered compounds. In carnotite-type compounds5 both uranyl and vanadyl bonds point toward the interlayer space occupied by the Mn+ metal ions and the corresponding Oyl atoms can established interactions with them. For example, in Ni(UO2)2V2O8·4H2O12 two Ni –Oyl (U) interactions, forming a quasi linear entity O = U = O – Ni – O = U = O, connect the layers; in Cu2(UO2)2V2O8(OH)2·6H2O4 two layers are connected

11



Page 12 of 28

by two Cu – Oyl (V) interactions through an entity V = O – Cu(OH)2Cu – O = V; in Ca(UO2)2V2O8·5H2O,60 the layers are connected by both Ca – Oyl (U) and Ca – Oyl (V) interactions (SI, Figure 2). The Y and Nd atoms connect two successive [(UO2)2V2O8] 2 layers through vanadyl oxygens O16 and O18 that pertain to V(1)O5 and V(3)O5 square pyramids, respectively (Figure 3 a and 3 b). As discussed by Wang et al. bond lengths in V = Oyl coordinating to Ln3+ centers are elongated in comparison with the terminal V = O length,9 in fact Ln3+ participate to the valence bond of the Oyl atom and, as a result of the competition between V = Oyl and Ln – Oyl bonding, V = O bond length increases with the Ln – O bond-valence (SI, Figure 3). The coordination polyhedra are completed by six water oxygens giving a distorted bicapped trigonal prism for Y and by seven water oxygens giving a distorted tricapped trigonal prism for Nd. For La, the stacking of the layers results from the connection of La to a vanadyl-oxygen of a V(3)O5 square pyramids and to a uranyl-oxygen of a U(3)O7 pentagonal bipyramid (Figure 3 c). As for vanadyls in the Y and Nd compounds, the formation of a La – O13 bond weakens the U = Oyl bond, the U(3) = O13 distance is 1.809(5) Å with respect to the U(3) = O14 distance of 1.797(4) Å involving terminal Oyl. The La – O13 bond valence is 0.192 vu; in Ni(UO2)2V2O8·4H2O,14 the Ni – O6 bond-valence is larger, 0.355 vu, and the U = Oyl bond length increases to 1.852(29) Å, the U = O distance involving terminal Oyl is 1.797(30) Å. The coordination of La is completed by eight water oxygens giving a distorted bicapped square antiprism. The coordination number (CN) of the rare earth increases from 8 for Y, to 9 for Nd and to 10 for La in agreement with the increase of the ionic radius. The polyhedra YO2(OH2)6, NdO2(OH2)7 and LaO2(OH2)8 are perfectly defined with Ln – O distances between 2.315(6) and 2.411(6) Å for Ln = Y, 2.460(20) and 2.619(16) Å for Ln = Nd and 2.542(5) and 2.784(5) Å for Ln = La, for each lanthanide atom the next distance is greater than 4Å. The average Ln – O distances, 2.356, 2.518 and 2.620 for Ln = Y, Nd and La, 12


Page 13 of 28 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


respectively, are in agreement with the sums of the ionic radii (rY3+ + rO2- = 2.40, rNd3+ + rO2- = 2.54, rLa3+ + rO2- = 2.65 Å).61 The bond-valence sums calculated using Brese and O’Keeffe data62 with b = 0.37 Å are 3.18, 3.13 and 3.01 vu. for Y, Nd and La, respectively.

V3

V3

3.

Environment

and

Y Nd La O

V3

b)

a)

Figure

U3

V1

V1

c)

oxygen

polyhedron

of

the

rare-earth

atom

in

a)

Y2[(UO2)2V2O8]3·20H2O, b) Nd2[(UO2)2V2O8]3·22H2O and c) La2[(UO2)2V2O8]3·20H2O. In the three compounds the [(UO2)2V2O8] 2 layers can be considered as pillared by Ln(H2O)n polyhedra giving neutral 3D lanthanide-uranyl-vanadate frameworks {(Y(H2O)6)2[(UO2)2V2O8]3},

3

{(Nd(H2O)7)2[(UO2)2V2O8]3},

and

3

3

{(La(H2O)8)2[(UO2)2V2O8]3} with eight non-coordinated water molecules for Ln = Nd, Y and four for Ln = La occupying the voids and connected to Ln-coordinated water molecules trough hydrogen bonds.

13



Page 14 of 28

Thermal Analysis The thermal comportment of the Y and La compounds will be described in details. The behaviour of the other compounds is similar to that of the Y uranyl-vanadate and will not be described. 1.

Thermal analysis of Y2[(UO2)2V2O8]3·20H2O. The DTA curve (Figure 4 a) exhibits several endothermic peaks between 20 and

300°C corresponding to successive dehydrations, however the different steps are not clearly highlighted on the TGA curve on which two inflexion points correspond to approximately to the deca- and the hexa-hydrates. In this temperature range (20 to 300°C), the HTXRD patterns evolution (Figure 4 b) does not evidence phase transition, except some little changes in the region +Vd.^d.*V at low temperature and an important continuous displacement of the (1 0 0) reflection due to a large diminution of the interlayer space during the dehydration. At 300°C the diffraction pattern corresponds to the totally dehydrated Y2[(UO2)2V2O8]3 compound. This decomposes at 565°C (exothermic peak) into U2V2O11, YVO4 and U3O8 evidenced on the PXRD pattern of the cooled sample. The experimental mass loss for the total dehydration (12.64%) confirms the number of water molecules deduced from the structure determination (theoretical mass loss, 12.98%). The number of water molecules found from the structure determination of the Nd and Eu9 compounds is also in agreement with the experimental mass losses for the total dehydration (SI, Table 1). For the other studied lanthanide compounds the number of water molecules calculated from the TGA analyses is 20 except for the heaviest, Yb (18 water molecules) (SI, Table 1).

14


a)

0

Y 2[(UO2)2V2O8]3420H2O

-2 -4 -6

Y 2[(UO2)2V2O8]3410H2O

-8

Y 2[(UO2)2V2O8]346H2O -10 -12

Y 2[(UO2)2V2O8]3

-14 0

100

200

300

400

500

600

700

T (°C)

b) T (°C)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Mass Loss (%)

Page 15 of 28

750°C

Y 2UVO4+U2V2O11+U3O8 565°C

Y 2[(UO2)2V2O8]3 300°C

Y 2[(UO2)2V2O8]3.xH2O x 20°C 10

20

30

40

50 26 (°)

Figure 4. a) DTA/TGA analysis and b) HTRXD patterns of Y2[(UO2)2V2O8]3·20H2O. 2.

Thermal analysis of La2[(UO2)2V2O8]3·20H2O. The HTXRD results (Figure 5 b) are totally different and exhibit three phase

transitions at about 80, 120 and 240°C. These transitions correspond on the TGA curve (Figure 5 a) to mass losses of about 2.61, 5.94, 3.76% corresponding to the formation of La2[(UO2)2V2O8]3·16H2O (theoretical mass loss = 2.60%), La2[(UO2)2V2O8]3·6H2O (5.88%) and La2[(UO2)2V2O8]3 (3.85%), respectively. The starting compound is stable up to 70°C without significant displacement of the (1 0 0) reflection (Figure 5 b, zoom 1), this temperature range corresponds to the loss of the four non-coordinated water molecules and to the first endothermic peak on the TGA. The diffraction pattern of the hexadeca-hydrate La2[(UO2)2V2O8]3·16H2O observed between 80 and 110°C shows a displacement of the (1 0

15



Page 16 of 28

0) reflection to higher .Z values (Figure 5 b, zoom 2) indicating a decrease of the interlayer space. At 120°C, the hexa-hydrate is formed, a new displacement of the (1 0 0) reflection to higher .Z values is observed, the XRD pattern evolves little up to 230°C, however at 210°C the reflection at about .^ = 31° is split (Figure 5 b, zoom 3) and the first refection of the weak doublet at about .^ = 44.5° disappears (Figure 5 b, zoom 4) which may correspond to the formation of the tri-hydrate. The formation of the tri-hydrate is marked by a slight inflection on the TGA curve (Figure 5 a) but is much more visible on the analysis reported in figure 7 carried out under other conditions. At 240°C, the XRD pattern, with a further decrease of the interlayer space, is that of the anhydrous compound La2[(UO2)2V2O8]3, which decomposes into U2V2O11, LaVO4 and U3O8 at about 600°C (exothermic peak). The experimental mass loss for the total dehydration (12.33%) confirm the number of water molecules deduced from the structure determination (theoretical mass loss, 12.21%).

16


Page 17 of 28 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60




Page 18 of 28

d (Å) 9,7

(CN=9)

9,6

Ce

Pr 9,5

Nd

9,4

La 9,3

Sm

(CN=8)

9,2

Gd

Y

Er

(CN=9)

Yb

9,1

(CN=10)

Eu

9 0,900

0,950

1,000

1,050

1,100

1,150

1,200

1,250

1,300

r (Å)

Figure 6. Variation of the interlayer distance (d = a

eD versus the ionic radius (r) of the

lanthanide ion61 for the compounds Ln2[(UO2)2V2O8]3·nH2O. Hydration-dehydration of the lanthanum uranyl-vanadate. As previously described, lanthanide uranyl-vanadates are dehydrated to the anhydrous phase prior to decomposition. To verify that the anhydrous phase is constructed with the same layers as the fully hydrated phase, the rehydration has been studied by TGA and HTXRD for the La compound. The lanthanum uranyl-vanadate was submitted to a cycle heating-cooling at 0.2° C min-1 under humid air sweep (3% water) up to 400 °C for TGA and 300°C for HTXRD to avoid decomposition. By heating some subtle differences appear compared to the experiments described previously and may be due to the difference in experimental conditions. However La2[(UO2)2V2O8]3·6H2O is obtained at 120°C and La2[(UO2)2V2O8]3 above 240°C; the formation of the tri-hydrate intermediate is not seen on the DXHT but is clearly marked on 18


Page 19 of 28

the TGA. On cooling the first step on the TGA (Figure 7 a) corresponds to the formation of the hexa-hydrate La2[(UO2)2V2O8]3·6H2O and the total mass gain is in agreement with the formation of La2[(UO2)2V2O8]3·20H2O. On the HTXRD (Figure 7 b), the pattern of La2[(UO2)2V2O8]3 disappears at 100°C and a bad crystallized phase is obtained, however the first reflection observed (1 0 0) move to the low .Z angles traducing an increase of the interlayer space correlated to water inclusion. The residue of the HTXRD study is maintained under air and, after seven days the pattern of the starting compound is found (Figure 8). Total dehydration of La2[(UO2)2V2O8]3·20H2O is reversible, confirming that the geometric isomer of the uranyl-vanadate is conserved during total dehydration.

a)

b) 100

Adsorbed Water

400

La2[(UO2)2V2O8]3=20H2O

T (°C)

450

Mass variation (%)

100°C

350

Cooling

300 250

90

La2[(UO2)2V2O8]346H2O

200

300°C

150

240°C

La2[(UO2)2V2O8]343H2O

100

La2[(UO2)2V2O8]3

50

80

Heating 120°C

0

0

10

20

30

40

50

60

Time (hr) 9

10

20

10

20

30

40

30

50

40

50

Figure 7. a) TGA and b) DXHT studies of the dehydration and rehydration of La2[(UO2)2V2O8]3·20H2O into La2[(UO2)2V2O8]3

Intensity (a.u.)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Before HTXRD

After 7 days

After 1 day

End of HTXRD 10

20

30

40

50

2 G (°)

19



Page 20 of 28

Figure 8. Evolution of the PXRD of the residue of the HTXRD study maintained under air. Crystal structure of La2[(UO2)2V2O8]3·6H2O The HTXRD study showed stabilization of the hexa-hydrate La2[(UO2)2V2O8]3·6H2O between 120 and 210°C. This stabilization involves not only the departure of the non-bonded water molecules but also the reorganization of the environment of the lanthanum atom. For study the role of La in this partially dehydrated structure, we have studied a single crystal as a function of the temperature. At 50 °C, the significant increase of the parameters a and indicates a clear decrease of the interlayer space (SI, Table 3). From 50 to 120°C, the slow increase of all the unit cell parameters is due to the thermal dilatation. During the X-ray data collection at 120°C, the crystal quickly deteriorated. Thus the X-ray data collection was performed at 50 and 70°C on another crystal. The results of the structure resolution and refinement are identical for the two temperatures and only the study at 70°C is reported. The structural study confirms that the observed transformation corresponds to the formation of the hexa-hydrate La2[(UO2)2V2O8]3·6H2O. Single crystal structure analyses confirm that dehydration occurs via a single-crystal-to-single-crystal (SCSC) transformation and yield insight into the role of water molecules upon dehydration. The unit cell parameters (Table 1) clearly show that the lattice parameters b and c of the two hydrates are similar. On the contrary, there is a significant change in the a-axis (-19.5%) and volume of the unit cell (27.8%) during the transition and the preservation of single crystallinity during this transition was rather unexpected. The uranyl vanadate layers in La2[(UO2)2V2O8]3·6H2O are similar to that of La2[(UO2)2V2O8]3·20H2O with the ud/du geometrical isomer, however they are more corrugated. The range of the U – Oyl bond distances is larger, from 1.711(30) to 1.842(30) Å (avg. 1.795 Å). The equatorial U – Oeq bond lengths vary from to 2.278(23) to 2.411(21) Å

20


Page 21 of 28 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(avg. 2.335 Å). The V – Oyl bond distances are 1.578(26), 1.600(28) and 1.636(27) Å for V1, V2 and V3 respectively. The main differences concern, of course, the role of the lanthanum ion and its environment. While in the icosa-hydrate eight water oxygens coordinate the La atom, in the hexa-hydrate, only three water oxygens coordinate the La atom. To compensate the decrease in the number of water molecules and to assume its coordination, lanthanum shares more oxygen with the layers, forcing the layers to get closer and to distort. In fact, the lanthanum atom shares three oxygen atoms with two successive uranyl-vanadate layers, two Oyl (O2 and O13) and one Oeq (O7) of a U2O7 dimer for one layer and two Oyl (O8 and O14) of two corner shared UO7 polyhedra and one Oyl (O16) of a VO5 square pyramid for the other layer (Figure 9 a). The lanthanum coordination is completed by three water oxygen atoms to form a distorted tricapped trigonal prism (Figure 9 b). The coordination number of La is 9 in La2[(UO2)2V2O8]3·6H2O instead of 10 in La2[(UO2)2V2O8]3·20H2O.

U3

U2

V1

U1

a)

U3

b)

La O

Figure 9. a) Environment and b) oxygen polyhedron of the La atom in La2[(UO2)2V2O8]3·6H2O.

21



Page 22 of 28

The results indicate that the existence of inorganic layers and the oriented motion of the layers between the 20- and 6- hydrated phases preserved the space group and the integrity of the single crystal, despite of remarkable changes of both planarity of the layers and their connection by La polyhedra. SCSC transitions are commonly found in MOFs63 but are much more rarely observed in layered inorganic compounds. CONCLUSION Ten rare-earth uranyl-vanadates with formula Ln2[(UO2)2V2O8]3·nH2O have been hydrothermally synthetized. All crystallize in monoclinic symmetry with P21/c space group and their structures are built from uranyl-vanadate layers of carnotite-type connected by Ln polyhedra to form a three-dimensional framework. The interlayer distance varies linearly with the ionic radius of the rare-earth ion except for La. In fact, structure determination for Ln = La, Nd, Y reveals that the uranyl-vanadate layers adopt two different geometrical isomers with sequence ud/du for the La compound and ud/du/du for the others and that the shift of the layers takes place in two perpendicular directions. So the connection of two consecutive layers by Ln atoms through one Oyl atom of each layer is different involving one Oyl of vanadyl ion and one Oyl of uranyl ion for Ln = La and Oyl of two vanadyl ions for the other rare-earth ions. The thermal behavior of the lanthanum compound is also different and reveals several structural transitions, in particular a spectacular single-crystal-to-single-crystal transformation during partial dehydration to the hexa-hydrate and a reversible dehydration/rehydration phenomenon upon removal and rebinding of the guest and coordination water molecules. Several reasons can be invoked to explain the different geometrical isomers of the carnotite-type layer, in particular the higher ionic radius of La3+ or its electronic configuration, however, as for organoammonium cations, it is difficult to prove the role of the

22


Page 23 of 28 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


cation used as countercation in hydrothermal syntheses.15,64 At most, in this case, it can be assumed that the lanthanide cation does not only have a role of charge balancing or space filling. ASSOCIATED CONTENT Accession codes CCDC 1894960-1894963 contain the supplementary crystallographic data for this paper. These data can be obtained free of charge via www.ccdc.cam.ac.uk/data_request/cif, or by emailing [email protected], or by contacting The Cambridge Crystallographic Data Centre, 12 Union Road, Cambridge CB2 1EZ, UK; fax: +44 1223 336033. Supporting Information

XRD patterns, connection of the carnotite-type layers in Ni, Cu, Ca carnotite-type compounds, V = O bond length versus Ln – O valence bond figures and mass loss during thermal decomposition, refined unit cell parameters and evolution of the unit cell parameters of a single crystal of La2[(UO2)2V2O8]3.20H2O during heating tables (pdf).

AUTHOR INFORMATION Corresponding Author *E-mail: [email protected] ORCID Saïd Obbade: 0000-0002-0172-6757 Francis Abraham: 0000-0002-1565-4299

Notes The authors declare no competing financial interest

23



Page 24 of 28

REFERENCES (1) Finch, R.: Murakami T. In Reviews in Mineralogy, Volume 38, Ribbe P.H.; Editor, Mineralogical Society of America, Washington, DCn, 1999. (2) Spano, T. L.; Dzik, E. A.; Sharifironizi, M.; Dustin, M. K.; Turner, M.; Burns, P. C. Thermodynamic investigation of uranyl vanadate minerals: Implications for structural stability. Am. Mineral. 2017, 102, 1149–1153. (3) Plasil, J. Crystal structure of vanuralite, Al[(UO2)2(VO4)2](OH)·8.5H2O. Z. Kristallogr. Cryst. Mater. 2017, 232, 807–814. (4) Piret, P. ; Declercq, J. P.; Wauters-Stoop, D. Structure cristalline de la sengierite. Bull. Mineral. 1980, 103, 176–178. (5) Appleman, D. E.; Evans, H .T. The crystal structures of synthetic anhydrous carnotite, K2(UO2)2V2O8, and its cesium analogue, Cs2(UO2)2VO8. Am. Mineral. 1965, 50, 825–842. (6) Dickens, P. G.; Stuttard, G .P.; Ball, R. G. J.; Powell, A. V.; Hull, S.; Patat S. Powder neutron diffraction study of the mixed uranium–vanadium oxides: Cs2(UO2)2(V2O8) and UVO5. J. Mater. Chem. 1992, 2, 161–166. (7) Abraham, F.; Dion, C.; Saadi, M. Carnotite Analogues: Synthesis, Structure and Properties of the Na1-xKxUO2VO4 Solid Solution C,j x j D: J. Mater. Chem. 1993, 3, 459– 463. (8) Botto, I. L.; Baran, E. J. Über Ammonium Uranyl Vanadat und die Produkte seiner thermischen Zersetzung. Z. Anorg. Allg. Chem. 1976, 426, 321–332. (9) Wang, Y.; Yin, X.; Zhao, Y.; Gao, Y.; Chen, L.; Liu, Z.; Sheng, D.; Diwu J., Chai, Z.; Albrecht-Schmitt T. E.; Wang, S. Insertion of trivalent lanthanides into uranyl vanadate layers and frameworks, Inorg. Chem. 2015, 54, 8449–8455. ( 0) Abraham, F.; Dion, C.; Tancret N.; Saadi M. Ag2(UO2)2V2O8 : a new compound with the carnotite structure, synthesis, structure and properties. Adv. Mater. Res. 1994, 511-525. ( 1) Shashkim, D. P. Crystalline structure of francevillite, Ba[UO2)2(VO4)2] 5H2O. Dokl. Akad. Nauk SSSR 1975, 220, 1410–1413. ( 2) Cesbron, F. Etude cristallographique et comportement thermique des uranyl-vanadates de Ba, Pb, Sr, Mn, Co et Ni. Bull. Soc. Fr. Minéral. Cristallogr. 1970, 93, 320–327. ( 3) Alekseev, E. V.; Suleimanov, E. V.; Chuprunov, E. V.; Fukin, G. K. Crystal Structure of Ba(VUO6)2. J. Struct. Chem. 2004, 45, 518–522. ( 4) Borene, J. ; Cesbron, F. Structure cristalline de l'uranyl-vanadate de nickel tetrahydrate Ni(UO2)2(VO4)2(H2O)4. Bull. Soc. Fr. Mineral. Cristallogr. 1970, 93, 426–432. ( 5) Rivenet, M.; Vigier, N.; Roussel P.; Abraham, F. Hydrothermal synthesis, structure and thermal stability of diamine templated layered uranyl-vanadates. J. Solid State Chem. 2007, 180, 712–724. ( 6) Li, Y.; Burns, P. C.; Gault, R. A. A new rare-earth-element uranyl carbonate sheet in the structure of bijvoetite-(Y). Can. Mineral. 2000, 38, 153–162. ( 7) Burns, P. C.; Miller M. L.; Ewing, R. C. U6+ minerals and inorganic phases: a comparison and hierarchy of structures. Can. Mineral. 1996, 34, 845–880. ( 8) Burns, P.C. U6+ minerals and Inorganic Compounds: Insights into an expanded structural hierarchy of crystal structures. Can. Mineral. 2005, 43, 1839–1894. ( 9) Mer, A.; Obbade, S.; Rivenet, M.; Renard, C.; Abraham, F. [La(UO2)V2O7][(UO2)(VO4)] the first lanthanum uranyl-vanadate with structure built from two types of sheets based upon the uranophane anion-topology. J. Solid State Chem. 2012, 185, 180–186.

24


Page 25 of 28 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(20) Chernorukov, N. G.; Suleimanov, E. V.; Knyazev, A. V.; Klimov, E. Yu. Synthesis, structure and properties of A(III)(VUO6)3.nH(2)O (A(III) = Y, La, Ce, Sm, Dy, Lu), Radiochem. 1999, 41, 515–519. (2 ) Tancret, N.; Obbade, S.; Abraham, F. Ab initio structure determination of uranyl divanadate (UO2)2V2O7 from powder X-ray diffraction data. Eur. J. Solid State Inorg. Chem. 1995, 32, 195–207. (22) Rodriguez-Carvajal, J. Recent advances in magnetic structure determination by neutron powder diffraction. Physica B: Physics of Condensed Matter 1993, 192, 55–69. (23) Caglioti, G.; Paoletti, A.; Ricci, F. Choice of Collimators for a Crystal Spectrometer for Neutron Diffraction, Nucl. Instrum. 1958, 3, 223–228. (24) SAINT Plus, version 5.00, Bruker Analytical X-ray Systems, Madison, WI, 1998. (25) Sheldrick, G.M. SHELXTL PC, Version 6.12, An Integrated System for Solving, Refining, and Displaying Crystal Structures from Diffraction Data, Siemens Analytical X-ray Instruments, Inc., Madison, WI, 2001. (26) Blessing, R. H. SADABS, Program for absorption correction using SMART CCD based on the method of Blessing, 1995. (27) Burns, P. C.; Ewing R. C.; Hawthorne, F. C. The crystal chemistry of hexavalent uranium: polyhedron geometries, bond-valence parameters, and polymerization of polyhedra. Can. Mineral. 1997, 35, 1551–1570. (28) Schindler, M.; Hawthorne, F. C.; Baur, W. H. Crystal Chemical Aspects of Vanadium: Polyhedral Geometries, Characteristic Bond Valences, and Polymerization of (VOn) Polyhedra. Chem. Mater. 2000, 12, 1248–1259. (29) Gasperin, M. Na2U207: Synthèse et structure d'un Monocristal. J. Less-Common Met. 1986, 119, 83–90. (30) IJdo, D.J.W.; Akerboom, S.; Bontenbal, A.; Crystal structure of \( and e(# 2U2O7: From Rietveld refinement using powder neutron diffraction data, J. Solid State Chem. 2015, 221, 1– 4. (3 ) Saine, M.-C. Synthèse et structure de K2U2O7 Monoclinique. J. Less-Common Met. 1989, 154, 361–365. (32) Yagoubi, S.; Obbade, S.; Dion, C.; Abraham, F. Crystal structures of Rb2U2O7 and Rb8U9O31, a new layered rubidium urinate. J. Solid State Chem. 2005, 178, 3218–3232. (33) Van Egmond A. B. Investigations on cesium uranates-VI. The crystal structures of Cs2U2O7. J. Inorg. Nucl. Chem. 1976, 38, 2105–2107. (34) Zachariasen, W. H. Crystal Chemical Studies of the 5f-Series of Elements. IV. The Crystal Structure of Ca(UO2)O2 and Sr(UO2)O., Acta Crystallogr. 1948, 1, 281–285. (35) Murphy, G.; Kennedy, B. J.; Johannessen B.; Kimpton, J. A.; Avdeev, M.; Griffith, C. S.; Thorogood, G. J.; Zhang, Z. Structural studies of the rhombohedral and orthorhombic monouranates: CaUO4, \( 4, e( 4 and BaUO4. J. Solid State Chem. 2016, 237, 86– 92. (36) Siegel, S.; Hoekstra, H. R. The Crystal Structure of Copper Uranium Tetroxide, Acta Crystallogr., Sect. B: Struct. Crystallogr. Cryst. Chem. 1968, 24, 967–970. (37) Cremers, T. L.; Eller, P. G.; Larson, E. M. Single-Crystal Structure of Lead Uranate(VI), Acta Crystallogr., Sect. C: Struct. Chem. 1986, 42, 1684–1685. (38) Volkringer, C.; Henry, N.; Grandjean, S.; Loiseau, T. Uranyl and/or Rare-Earth Mellitates in Extended ? [- & ? Networks: A Unique Case of Heterometallic " & [" & Interaction with UVI = O [ LnIII Bonding (Ln = Ce, Nd). J. Am. Chem. Soc. 2012, 134, ./*[ .'3:

25



Page 26 of 28

(39) Tian, T.; Yang, W.; Wang, H.; Dang, S.; Sun, Z.-M. Flexible Diphosphonic Acids for the Isolation of Uranyl Hybrids with Heterometallic UVI = O – ZnII " & [" & Interactions. Inorg. Chem. 2013, 52, '.''['.+,: (40) Sullivan, J. C.; Zielen, A. J.; Hindman, J. C. Specific Interaction between Np(V) and U(VI) in Aqueous Perchloric Acid Media. J. Am. Chem. Soc. 1961, 83, 3373–3378. (4 ) Krivovichev, S. V. Crystal Structure of KNa3[(UO2)5O6(SO4)]. Radiochem. 2008, 50, 450–454. (42) Krot, N .N.; Grigoriev, M. S. Cation-cation interaction in actinide compounds, Russ. Chem. Rev. 2004, 73, 89–100. (43) Wang, S.; Alekseev, E. V.; Depmeier, W.; Albrecht-Schmitt, T. E. K(NpO2)3(H2O)Cl4 : A Channel Structure Assembled by Two- and Three-Center Cation Cation Interactions of Neptunyl Cations Inorg. Chem. 2011, 50, 4692–4. (44) Forbes, T. Z; Burns, P. C.; Skanthakumar, S.; Soderholm, L. Synthesis, Structure, and Magnetism of Np2O5, J. Am. Chem. Soc. 2007, 129, 2760–2761. (45) Forbes, T. Z.; Wallace, C.; Burns P. C. Neptunyl Compounds: Polyhedron geometries, Bond-valence Parameters, and Structural Hierarchy, Can. Mineral. 2008, 46, 1623–1645. (46) Morrison, G., Read, C. M. Smith, M. D., zur Loye, H.-C. Flux crystal growth and structural analysis of two cesium uranium oxides, Cs2.2U5O16 and Cs2U4O13, containing multiple cation – cation interactions, CrystEngComm 2015, 17, +L'[ +/4: (47) Li, Y.; Cahill, C.L.; Burns, P.C. Synthesis, Structural Characterization, and Topological Rearrangement of a Novel Open Framework U–O Material: (NH4)3(H2O)2{[(UO2)10O10(OH)][(UO4)(H2O)2]}, Chem. Mater. 2001, 13, 4026 – 4031. (48) Kubatko, K.-A.; Burns, P. C. " & [" & Interactions in Sr5(UO2)20(UO6)2O16(OH)6(H2O6) and Cs(UO2)9U3O16(OH)5, Inorg. Chem. 2006, 45, ,.//[ ,.' : (49) Read, C. M.; Yeon, J.; Smith, M. D.; zur Loye, H.-C. Crystal growth, structural characterization, cation–cation interaction classification, and optical properties of uranium(VI) containing oxychlorides, A4U5O16Cl2 (A = K, Rb), Cs5U7O22Cl3 , and AUO3Cl (A = Rb, Cs), CrystEngComm 2014, 16, /.*+[/./L: (50) Alekseev, E. V.; Krivovichev, S. V.; Depmeier, W. Crystal chemistry of anhydrous Li uranyl phosphates and arsenates. II. Tubular fragments and cation–cation interactions in the 3D framework structures of Li6[(UO2)12(PO4)8(P4O13)], Li5[(UO2)13(AsO4)9(As2O7)], Li[(UO2)4(AsO4)3] and Li3[(UO2)7(AsO4)5O)], J. Solid State Chem. 2009, 182, 2977–2984. (5 ) Obbade, S.; Dion, C.; Rivenet, M.; Saadi, M.; Abraham, F. A novel open-framework with non-crossing channels in the uranylvanadates A(UO2)4(VO4)3 (A=Li, Na), J. Solid State Chem. 2004, 177, 2058–2064. (52) Chippindale, A. M.; Dickens, P. G.; Flynn, G. J.; Stuttard, G. P. Crystal structures of U2V2O11 and UV2O8, J. Mater. Chem. 1995, 5, 141–146. (53) Obbade, S.; Yagoubi, S.; Dion, C.; Saadi, M.; Abraham, F. Two new lithium uranyl tungstates Li2(UO2)(WO4)2 and Li2(UO2)4(WO4)4O with framework based on the uranophane sheet anion topology, J. Solid State Chem. 2004, 177, 1681–1694. (54) Alekseev, E. V.; Krivovichev, S. V.; Depmeier, W.; Siidra, O. I.; Knorr, K.; Suleimanov, E. V.; Chuprunov, E. V. Na2Li8[(UO2)11O12(WO5)2]: Three Different Uranyl-Ion Coordination Geometries and Cation–Cation Interactions, Angew. Chem., Int. Ed. 2006, 45,7233–7235. (55) Sullens T. A.; Jensen, R. A.; Shvareva, T. Y.; Albrecht-Schmitt, T. E. Cation – Cation Interactions between Uranyl Cations in a Polar Open-Framework Uranyl Periodate, J. Am. Chem. Soc. 2004, 126, 2676–2677.

26


Page 27 of 28 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(56) Morrison, J. M.; Moore-Shay, L. J.; Burns, P. C. U(VI) Uranyl Cation - Cation Interactions in Framework Germanates, Inorg. Chem. 2011, 50, 2272–2277 (57) Serezhkin, V. N., Trunov, V. K.; Makarevich, L. G. The refined crystal structure of uranyl molybdate, Kristallografiya 1980, 25, 858–860. (58) Alekseev, E. V.; Krivovichev, S. V.; Malcherek, T.; Depmeier, W. One-Dimensional Array of Two- and Three-Center " & [" & Bonds in the Structure of Li4[(UO2)10O10(Mo2O8)], Inorg. Chem. 2007, 46, '44.['444: (59) Brandenburg, N. P.; Loopstra, B. O.; e( ) sulphate and uranyl selenite, Acta Crystallogr., Sect. B: Struct. Crystallogr. Cryst. Chem. 1978, 34, 3/34[3/3L: (60) Burciaga-Valencia, C.; Reyes-Cortes, M.; Reyes-Rojas, A.; Renteria-Villalobos, M.; Esparza-Ponce, H.; Fuentes-Cobas, L.; Fuentes-Montero, L.; Silva-Saenz, M.; Herrera-Peraza, E.; Munoz, A., Montero-Cabrera, M. E. Characterization of uranium minerals from Chihuahua using synchrotron radiation, Revista Mexicana de Fisico, 2010, 56, 75–81. (61) Shannon, R. D. Revised Effective Ionic Radii and Systematic Studies of Interatomic Distances in Halides and Chalcogenides. Acta Crystallogr., Sect. A: Cryst. Phys., Diffr., Theor. Gen. Crystallogr. 1976, 32, 751–767. (62) Brese, N. E.; O’Keeffe, M. Bond-Valence Parameters for Solids, Acta Crystallogr., Sect. B: Struct. Sci. 1991, 47, 192–197. (63) Sun, H-L.; Yin, D-D.; Chen, Q.; Wang, Z. Europium Pyrimidine-4,6-dicarboxylate Framework with a Single-Crystal-to-Single-Crystal Transition and a Reversible Dehydration/ Rehydration Process, Inorg. Chem. 2013, 52, 3*'.[3*'4: (64) Almond, P. M.; Albrecht-Schmitt, T. E. Do Secondary and Tertiary Ammonium Cations Act as Structure-Directing Agents in the Formation of Layered Uranyl Selenites? Inorg. Chem. 2003, 42, 5693–5698.

27



Page 28 of 28

For Table of Contents Use Only

Structural Evolution in the Rare-Earth Uranyl-vanadates Ln2[(UO2)2V2O8]3·nH2O, Singularity of the Lanthanum Compound and Single-Crystal-to-Single-Crystal Partial Dehydration.

Alexandre Mer, Saïd Obbade, Philippe Devaux, Francis Abraham

Ln2[(UO2)2V2O8]3=nH2O La2[(UO2)2V2O8]3=20H2O La2[(UO2)2V2O8]3=6H2O Ln = Y, n=20 Ln = Nd, n=22

B

= 9.11Å

SCSC transformation

9.39Å

9.45Å

7,08Å

The rare-earth uranyl-vanadates Ln2[(UO2)2V2O8]3·nH2O are built from carnotite-type layers connected by Ln atoms through interactions involving vanadyl oxygens. For Ln = La the layers adopt another geometrical isomer and the connection involves vanadyl and uranyl oxygens. Upon dehydration the La compound undergoes a single-crystal-to-single-crystal transformation.

28


Structural Evolution in the Rare-Earth Uranyl Vanadates Ln2[(UO2

Recommend Documents