Sr2OsO5 and Sr7Os4O19, Two Structurally Related, Mott Insulating

Article pubs.acs.org/IC

Sr2OsO5 and Sr7Os4O19, Two Structurally Related, Mott Insulating Osmates(VI) Exhibiting Substantially Reduced Spin Paramagnetic Response Shrikant A. Mohitkar,† Walter Schnelle,† Claudia Felser,† and Martin Jansen*,†,‡ †

Max-Planck-Institut für Chemische Physik fester Stoffe, Nöthnitzer Straße 40, 01187 Dresden, Germany Max-Planck-Institut für Festkörperforschung, Heisenbergstr. 1, 70569 Stuttgart, Germany

‡

S Supporting Information *

ABSTRACT: The new osmates(VI), Sr2OsO5 and Sr7Os4O19, feature quasi-1-D polyoxo anions, consisting of corner sharing [OsO6] octahedra. In both compounds, the magnetic moment at T = 300 K is significantly lower (1.2−1.3 μB/Os-atom) than the value expected for S = 1. For neither of the new osmates(VI) is any evidence for long-range magnetic order found. For Sr7Os4O19, magnetic susceptibility suggests an antiferromagnetic ordering at TN = 43(3) K; however, no corresponding anomaly is visible in specific heat. Both compounds are semiconductors.

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INTRODUCTION Atomic attributes as there are spin−orbit couplings (SOC), Coulomb correlations, and spatial extension of the atomic orbitals follow specific trends with growing atomic number and crucially determine the electronic structure of a given chemical configuration. For the late 4d and 5d transition elements, the contributions of these quantities to the electronic state energies are in the same order of magnitude, and as a consequence, the relevant parameters for extended solids, i.e., bandwidth (W), SOC, and on-site Coulomb repulsion (U), are of an approximately equal energy scale. Superimposed crystal field (CF) effects may further crucially affect the nature of the electronic states. These facts are substantially contributing to the complexity of respective materials; however, they are offering at the same time great opportunities for realizing exciting electronic phases. Marked discoveries, e.g., of superimposed ferromagnetism and superconductivity in Sr2RuO4,1 realizations of the Kitaev scenario2 in oxoiridates,3 or an unconventional square-planar coordination of 5d5 configurated iridium(IV) in Na4IrO4,4 are illustrative manifestations of the conditions mentioned. Recently, osmium, which belongs to the same group of “platinum metals”, has come into the focus in this context. As a conspicuous common feature, complex oxides of high valent (5+, 6+, and 7+) osmium (1) show a considerably reduced paramagnetic response, far below the expected spin-only values, and (2) are Mott insulators (for a compilation of pertinent examples, see ref 5). Various explanations for the peculiar observations have been suggested. For Na2OsO4, where Os(VI) is located in a drastically distorted (uniaxially compressed) octahedral environment, the damped paramagnetic response has been attributed to a CF-induced splitting of the t2g band and an S = 0 ground state.6 However, © XXXX American Chemical Society

the same phenomena are displayed as well by ordered and undistorted cubic double perovskites (DP) Ba2AOsO6 (A = Na, Ca, Y).7−11 Here, it has been demonstrated convincingly that strong electronic correlations and large SOC are the key factors of influence. In particular, SOC is reported to be essential in opening the gap, classifying these DP as “Dirac-Mott” correlated insulators.12,13 Since the features discussed appear to be pronounced strongest in oxido-osmates, we have regarded it appropriate to broaden the basis of respective materials by experimentally screening osmium-based ternary alkaline and alkaline-earth oxides more profoundly for unknown phases. More specifically, we have been targeting still elusive Ba2OsO4 or Sr2OsO4, which we expect to exhibit special electronic properties comparable to the prominent ruthenium and iridium analogues. Here, we report on structural and basic physical characterizations of Sr2OsO5 and Sr7Os4O19. The new osmates(VI) are structurally related. Sr2OsO5 features a quasi-one-dimensional polyoxo anion of cis-corner sharing octahedra, while in Sr7Os4O19, two such chains are condensed via corner sharing. Both oxides are nonmetallic and show significantly reduced paramagnetic response compared to the spin-only value for the S = 1 state. The most prominent alkali oxo-osmate reported so far is superconducting KOs2O6,14,15 while NaOsO3,16,17 Na2OsO4,6 and Na 3OsO 518 feature interesting collective magnetic phenomena, and LiOsO319 or Li7OsO620 show particular dielectric and transport properties. First reports on synthesis and crystal structures of alkaline-earth osmates focused on the Received: June 7, 2016

A

DOI: 10.1021/acs.inorgchem.6b01354 Inorg. Chem. XXXX, XXX, XXX−XXX

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Inorganic Chemistry perovskites and pyrochlores CaOsO3,21 Ba2MOsO6 (M = Li, Na),7 Ba11Os4O24,22 and Ca2Os2O7,23,24 respectively.

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3Sr7Os4O19 = 7Sr3OsO6 + = ∼24%)

EXPERIMENTAL SECTION

Description of Crystal Structures. Sr2OsO5 adapts a structure type known for some ternary alkali pentafluorides like Rb2CrF526 and Rb2FeF5,27 as well as for the oxides Ba2ReO5,28 Ba2WO5,29 and Sr2WO5.30 The laboratory PXRD pattern (Figure 1) taken at RT was successfully refined assuming the

Sr2OsO5 and Sr7Os4O19 were synthesized as polycrystalline powders by reacting SrO2, OsO2, and Os metal at 1073 K in an evacuated sealed quartz ampule. SrO2 (Aldrich, 99%) and Os metal powder (Chempur, 99.9%) were used as received. As purchased OsO2 (SigmaAldrich, 83% Os) was containing ∼30% of osmium metal and was, therefore, oxidized by heating with a stoichiometric amount of PbO2 at 723 K in an evacuated sealed quartz ampule to get highly pure OsO2. A typical synthetic batch for Sr2OsO5 consisted of a mixture of SrO2 (134 mg), ∼12% excess of OsO2 (142 mg), and Os metal powder (8 mg); that of Sr7Os4O19 consisted of a mixture of SrO2 (249 mg), OsO2 (264 mg) and Os metal powder (32 mg). The starting mixtures were ground thoroughly inside a glovebox and pressed into pellets that were placed in corundum containers and finally sealed in evacuated quartz ampules of approximately 2 cm diameter and 20 cm length. Single phase polycrystalline Sr2OsO5 and Sr7Os4O19 were obtained after 24 h of heating at 1073 K. The heating and cooling rates were kept at 80 K h−1, throughout. After the reactions being completed, the tubes were taken out of the furnace and opened in a glovebox. It was found that the presence of osmium metal is crucial to avoid the formation of any Os(VII) containing side phases. Thermogravimetric (TGA) analysis of Sr2OsO5 and Sr7Os4O19 were carried out on a Netzsch STA 449 C analyzer. The samples (≈20 mg) were placed in corundum crucibles, which were heated and cooled back at a rate of 5 K min−1 in the range of 25−1200 °C under dynamic argon flow. Laboratory powder X-ray diffraction (PXRD) studies at RT were performed with a HUBER G670 imaging plate Guinier camera with Cu−Kα1 radiation (λ = 1.5406 Å), covering a 2θ range of 5−85°. Rietveld refinements were carried out with the program TOPAS4.2.0.2 (AXS).25 The refined parameters were scale factor, zero point of θ, sample displacement (mm), and background as a Chebychev polynomial of 20th degree and 1/x function, crystallite size, microstrain, cell constants, atomic coordinates, and thermal parameters. Magnetization was measured in fields up to μ0H = 7 T in a MPMSXL7 magnetometer (Quantum Design). The susceptibility of Sr2OsO5 was dependent on field, indicating the presence of a ferromagnetic impurity. The data were corrected using the Honda−Owen method (extrapolation of χ(1/H) to 0). The electrical resistivity was determined on powders pressed in a sapphire die cell with Pt contacts using the van der Pauw method and direct current. Heat capacity was measured by a relaxation method (HC option, PPMS, Quantum Design).

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Figure 1. PXRD patterns of Sr2OsO5 and Sr7Os4O19 at RT (blue squares, observed; red spheres, fit from Rietveld refinement; gray line, difference curve; lower black bars, Bragg peaks).

orthorhombic space group Pnma (No. 62), with the final lattice parameters a = 7.1569(5) Å, b = 5.5343(4) Å, and c = 10.9094(8) Å (Table 1). Sr2OsO5 displays a quasi-onedimensional polyoxo anion, an [OsO4/1O2/2] infinite chain extending along the b axis, interleaved with 10-fold coordinated strontium atoms (Figure 2a−c (left)). Two adjacent vertices of OsO6 octahedra are shared, thus forming a cis-type connectivity (Figure 3, top). The Os−O bond lengths agree, on average, well with the data reported in the literature,6,18 and with the sum of ionic radii. The Os−O(2) distance of 2.010(1) Å of common vertices and the Os−O(3) bond length of 1.956(1) Å opposite to the shortest terminal bonds are substantially longer than the other three Os−O separations to give facially (trigonal) distorted octahedral geometry (Table 2). The O(1)−Os−O(1) and O(1)−Os−O(4) angles are larger than O(2)−Os−O(2) and O(2)−Os−O(3) and thus reflect the distortion of OsO6 octahedra mentioned (Table 2). Further-

RESULTS AND DISCUSSION

Synthesis and Chemical Properties of Sr2OsO5 and Sr7Os4O19. Sr2OsO5 and Sr7Os4O19 were synthesized by solidstate reactions in an evacuated sealed quartz ampule by heating mixtures of appropriate reactants at 1073 K for 24 h. Black, airstable microcrystalline powders of Sr2OsO5 and Sr7Os4O19 were obtained. The TGA analysis shows that both the compounds are stable up to ∼600 °C, above which decomposition starts. After a few poorly resolved stages of weight loss, Sr3OsO6 remains as a major solid residue, in both cases. 3Sr2OsO5 = 2Sr3OsO6 +

5 15 Os + OsO4 (wt loss 4 4

1 3 Os + OsO4 (wt loss 4 4

= ∼18%) B

DOI: 10.1021/acs.inorgchem.6b01354 Inorg. Chem. XXXX, XXX, XXX−XXX

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Inorganic Chemistry Table 1. Crystallographic Data Obtained from Structure Refinements of Sr2OsO5 and Sr7Os4O19 Sr2OsO5

Sr7Os4O19

crystal system space group (No.) lattice parameters

orthorhombic Pnma (62) a = 7.1569(5) (Å) b = 5.5343(4) (Å) c = 10.9094(8) (Å)

V (Å3) Rp (%) Rwp (%) Rexp (%) goodness of fit

432.108(5) 4.69 6.34 2.57 2.47

monoclinic C2/m (12) a = 13.6518(1) (Å) b = 5.5594(6) (Å) c = 10.3989(5) (Å) β = 98.42(5)° 780.731(1) 4.94 6.96 2.96 2.35

Figure 3. Projection of the chain structure of Sr2OsO5 (top) and Sr7Os4O19 (bottom). OsO6 octahedra are shaded in cyan. Bond lengths are in Å.

Table 2. Selected Bond Distances (Å) and Angles (deg) for Sr2OsO5 atoms Sr1−O3 Sr1−O3 Sr1−O1 Sr1−O2 Sr1−O4 Sr1−O1 Sr2−O1 Sr2−O4 Sr2−O3 Sr2−O1 Sr2−O2 Sr2−O4 Os−O4 Os−O1 Os−O3 Os−O2 atoms

Figure 2. Projections of the crystal structure of Sr2OsO5 (left) and Sr7Os4O19 (right): (a) view along [100], (b) view along [010], (c) view along [001]. OsO6 octahedra are shaded in cyan.

O4−Os−O1 O4−Os−O2 O4−Os−O3 O1−Os−O1 O1−Os−O2 O1−Os−O2 O1−Os−O3 O2−Os−O2 O2−Os−O3 Os−O2−Os

more, the bridging angle of 180° between Os−O(2)−Os is ideal for all centrosymmetric variants of this structure type. For Sr7Os4O19, the laboratory PXRD pattern (Figure 1) taken at RT was successfully refined in the monoclinic space group C2/m (No. 12). The lattice parameters obtained are a = 13.6518(1) Å, b = 5.5594(6) Å, c = 10.3989(5) Å, and β = 98.42(5)° (Table 1). Sr7Os4O19 adapts the Sr7Re4O1931 structure type and consists of infinite cis-bridged chains of the OsO6 octahedra connected by common vertices. One such chain is connected with another by corner sharing of every second OsO6 octahedron. These infinite strands are interleaved by 10- and 12-fold coordinated Sr atoms (Figure 2a−c (right)). C

dist.

multi.

2.445(1) 2.449(1) 2.630(8) 2.717(1) 2.773(8) 2.810(8) 2.517(7) 2.587(1) 2.802(2) 2.851(8) 2.859(2) 2.903(1) 1.827(1) 1.921(8) 1.956(1) 2.010(1)

1 1 2 2 2 2 2 1 2 2 2 1 1 2 1 2 angle 94.39(2) 85.15(0) 166.29(6) 98.60(3) 87.20(2) 174.20(2) 94.53(2) 87.00(0) 84.92(0) 180.00

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Inorganic Chemistry The Os(1)−O(3) bond of 2.032(2) Å and the Os(1)−O(7) distance of 1.999(3) Å of common vertices are substantially longer than the other three Os(1)−O separations to give facially (trigonal) distorted octahedral geometry; similarly, the Os(2)−O(3) bond of 1.965(2) Å of common vertices and the Os(2)−O(4) distance of 1.899(2) Å are longer than the other three Os(2)−O separations (Table 3). The average Os−O bond lengths are 1.95 and 1.90 Å for Os(1) and Os(2) atoms, respectively, and are in good agreement with the data reported in the literature,6,18 and with the sum of ionic radii. Sr atoms have two different coordinations: Sr(1) and Sr(4) are 12coordinated, while Sr(2) and Sr(3) are coordinated by 10 nearest oxygen neighbors. The structures of Sr2OsO5 and Sr7Os4O19 are closely related to each other. Sr2OsO5 contains OsO6 octahedra linked by common vertices, forming infinite cis-bridged monomeric chains, while the Sr7Os4O19 structure consists of two infinite chains of corner sharing OsO6 octahedra (same as found in Sr2OsO5) connected with each other to form dimers of the former single chains of octahedra (Figure 3, bottom). Magnetic and Thermal Properties. The magnetic susceptibility χ(T) of Sr2OsO5 is small (Figure 4; χ ≈ 1.1 × 10−3 emu mol−1 at T = 20 K), similar, to that observed for Na2OsO4.6 The effective moment derived from the product χT is 1.29 μB at T = 300 K and decreases with decreasing T toward zero. Alternatively, in the temperature range of 200−400 K, χ(T) may be described by a Curie−Weiss law with the effective moment μeff = 1.97 μB and θP = −402 K. Such a description may, however, be misleading. The deduced low μeff is compatible with the S = 1 state of the 5d2 configuration, together with a drastic reduction of the moment, probably by strong SOC. There is no indication for a long-range magnetic ordering in Sr2OsO5. A weak ferromagnetic signal (max. 0.00020 μB based on the molar mass of the target phase) visible in low-field data which sets in at TC = 9 K might be due to a minor ferromagnetic impurity phase. The specific heat cp(T) of Sr2OsO5 (Figure 5) does not show any anomaly at T = 9 K and it is not influenced by magnetic fields up to μ0H = 9 T. Below T = 6 K (Figure 5, inset), it follows the simple dependence cp(T) = γT + βT3 with γ = 0.36(2) mJ mol−1 K−2 and β = 0.399(1) mJ mol−1 K−4, the latter corresponding to a Debye temperature θD = 339 K. γ is small and indicates a very low concentration of defects. The visible deviation from the Debye T3 behavior at relatively low temperatures T/θD is due to the anisotropic character of the compound. Sr7Os4O19 displays even weaker magnetism (Figure 4; χ < 0.8 × 10−3 emu mol−1 per Os-atom) than Sr2OsO5. The temperature dependence of the effective moment derived from χT is similar to that of Sr2OsO5. At T = 300 K, it is 1.19 μB and decreases toward zero with decreasing T. Only at high temperatures (200−400 K) the χ(T) data may be fitted by a Curie−Weiss law with μeff = 2.70 μB/Os-atom and θP = −1250 K. Interestingly, this effective moment agrees well with the S = 1 state. The large negative θP would signify very strong antiferromagnetic interactions. (Remarkably similar values of μeff and θP were obtained from a simple Curie−Weiss fit for the 5d4 system SrOsO3: μeff = 2.659 μB, θP = −1028 K).32 Such a simple Curie−Weiss analysis thus has to be taken with great caution. In contrast to Sr2OsO5, a clear cusp-like anomaly is observed at TN = 43(3) K for Sr7Os4O19. Such a pronounced anomaly cannot be due to an impurity phase; thus it indicates the

Table 3. Selected Bond Distances (Å) and Angles (deg) for Sr7Os4O19 atoms Sr1−O1 Sr1−O6 Sr1−O3 Sr1−O6 Sr1−O1 Sr1−O7 Sr1−O2 Sr2−O4 Sr2−O2 Sr2−O1 Sr2−O4 Sr2−O5 Sr2−O3 Sr3−O5 Sr3−O2 Sr3−O5 Sr3−O2 Sr3−O4 Sr3−O3 Sr4−O1 Sr4−O6 Sr4−O3 Sr4−O7 Os1−O1 Os1−O5 Os1−O7 Os1−O3 Os2−O6 Os2−O2 Os2−O4 Os2−O3 atoms O1−Os1−O1 O1−Os1−O5 O1−Os1−O7 O1−Os1−O3 O1−Os1−O3 O5−Os1−O7 O5−Os1−O3 O7−Os1−O3 O3−Os1−O3 O6−Os2−O2 O6−Os2−O4 O6−Os2−O3 O2−Os2−O2 O2−Os2−O4 O2−Os2−O3 O2−Os2−O3 O4−Os2−O3 O3−Os2−O3 Os2−O3−Os1 Os1−O7−Os1

dist.

multi.

2.670(2) 2.677(3) 2.782(3) 2.804(4) 2.825(2) 2.900(4) 2.939(2) 2.341(2) 2.611(2) 2.630(2) 2.782(3) 2.827(5) 3.006(3) 2.484(3) 2.520(2) 2.530(3) 2.741(2) 2.792(2) 2.808(2) 2.654(2) 2.685(3) 2.756(2) 2.780(0) 1.856(2) 1.928(3) 1.999(3) 2.032(2) 1.838(2) 1.869(2) 1.899(2) 1.965(2)

2 1 2 2 2 1 2 1 2 2 1 2 2 1 2 1 2 2 2 4 2 4 2 2 1 1 2 1 2 1 2 angle 97.69 (8) 98.96(7) 87.26(6) 88.15(8) 170.62(8) 170.48(8) 87.31(7) 85.69(7) 85.16(9) 98.92(7) 166.52(1) 81.52(8) 96.26(8) 90.03(7) 177.38(9) 86.21(8) 89.09(8) 91.31(9) 170.44(1) 180.00

presence of magnetic Os species (a nominal S = 1 state) in Sr7Os4O19 and their antiferromagnetic long-range ordering. If θP is a realistic measure for the magnetic dominating exchange interaction, the large ratio of θP/TN would indicate strong frustration by competing interactions. For lower measurement D

DOI: 10.1021/acs.inorgchem.6b01354 Inorg. Chem. XXXX, XXX, XXX−XXX

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Inorganic Chemistry

and 0.15 eV for Sr7Os4O19, respectively. These values represent minimum estimates for the fundamental energy gaps which may be much larger.

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CONCLUSIONS At the current stage of investigations, we cannot draw definitive conclusions on the magnetic ground states of the two osmates. The weak magnetism exhibited by these 5d2 systems is difficult to address by magnetochemistry methods. The effective moments and the large θP values resulting from simplistic Curie−Weiss analyses applied to high-T susceptibility data may not be meaningful since the leading exchange interaction could be grossly overestimated by θP, especially in the case of Sr7Os4O19. However, such large θP are observed in almost all Os 5d2 compounds. For Sr2OsO5, no indication for magnetic ordering and thus for magnetic Os species is observed in our bulk probes. The magnetic moment is within a range which can be achieved within the nominal S = 1 state and where the moment is heavily suppressed by SOC. Shi et al.6 reasoned that the axial (tetragonal) compression of the octahedra in the edgeconnected chain compound Na2OsO4 is remarkably strong and may actually justify a S = 0 scenario. In Sr2OsO5, the sizable trigonal distortion of the OsO6 octahedra may also motivate this description; however, presently we cannot say which effect (CF or SOC) will prevail, and thus cannot draw a traditional term splitting scheme12,13 for Os 5d2 in the two compounds. For Sr7Os4O19, we observe the signature of long-range order in magnetic susceptibility but no corresponding anomaly in specific heat. While the Os species are certainly in a magnetic (S = 1) state in this compound, it is not yet clear if the Os moments show long-range order. Since in 5d2 S = 1 compounds, the ordered magnetic moments may be well below ∼0.5 μB, they also might be not detectable in magnetic neutron diffraction measurements, as, e.g., in the case of the Ba2CaOsO6 double perovskite.9 It has been pointed out that, in 5d2 systems with large SOC, more exotic ground states may be realized as well,12 provided the orbital degeneracy is not lifted as in the cubic Os double perovskites. Since we have lower site symmetry of the Os ions in both compounds, we expect some kind of antiferromagnetic order at low temperatures. With the method of muon spin rotation spectroscopy, it could be possible to detect ordered moments in the two osmates. Finite linear terms are observed for the specific heat at low temperature. Such linear terms are frequently observed in polycrystalline semiconductors samples and are due to point defects. In this respect, the Sr2OsO5 sample should have less point defects than the Sr7Os4O19 material. Concerning the electronic transport, both compounds show activated conduction behavior. Because of the lack of sizable single crystals, it is not possible to address any questions on the anisotropy of these chain-type structures. We can classify both compounds as Mott-type insulators with relatively small energy gaps at the Fermi level. In addition to the correlations, the strong spin−orbit coupling may drive these two compounds insulating and qualify them as Dirac-Mott type insulators.

Figure 4. Temperature dependence of the inverse magnetic susceptibility H/M per Os atom for Sr2OsO5 and Sr7Os4O19 measured in magnetic fields of μ0H = 3.5 T (green squares) and 7.0 T (red spheres). The corrected data (orange crosses; see text) for Sr2OsO5 or the data above T = 200 K for Sr7Os4O19 were used for the Curie− Weiss fits (black lines; see text). The inset shows the temperature dependence of the electric resistivity of both compounds.

Figure 5. Temperature dependence of specific heat divided by temperature, cp/T, for Sr2OsO5 and Sr7Os4O19. The specific heat data are per mol-Os and, for better visibility, the curve for Sr7Os4O19 is shifted upward by 0.1 units. The inset shows the same data cp/T as a function of T2 for temperatures T < 10 K.

fields, a small step due to a ferromagnetic impurity phase with TC ≈ 170 K becomes visible. In the specific heat of Sr7Os4O19 (Figure 5), there is, however, no indication for a magnetic ordering transition around TN = 43 K. This may be due to the small ordered magnetic moment often observed for Os 5d2 compounds.5,9 The specific heat below at low temperatures (Figure 5 inset) is well described by cp(T) = γT + βT3 with γ = 2.17(1) mJ molOs−1 K−2 and β = 0.432(1) mJ mol-Os−1 K−4. Similar to Sr2OsO5, the derived Debye temperature θD = 323 K and there is no significant field dependence of cp(T). The larger value of γ indicates a significantly higher concentration of point defects compared to Sr2OsO5. The electrical resistivity data ρ(T) measured below 320 K on both compounds (Figure 4, inset) demonstrate their semiconducting behavior. The activation energies (impurity level gaps) derived from data above 250 K are 0.28 eV for Sr2OsO5

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ASSOCIATED CONTENT

S Supporting Information *

The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acs.inorgchem.6b01354. E

DOI: 10.1021/acs.inorgchem.6b01354 Inorg. Chem. XXXX, XXX, XXX−XXX

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(22) Wakeshima, M.; Hinatsu, Y. Solid State Commun. 2005, 136, 499. (23) Reading, J.; Knee, C. S.; Weller, M. T. J. Mater. Chem. 2002, 12, 2376. (24) Zheng, P.; Shi, Y. G.; Wu, Q. S.; Xu, G.; Dong, T.; Chen, Z. G.; Yuan, R. H.; Cheng, B.; Yamaura, K.; Luo, J. L.; Wang, N. L. Phys. Rev. B: Condens. Matter Mater. Phys. 2012, 86, 195108. (25) TOPAS-V4.2.0.2: General Profile and Structure Analysis Software for Powder Diffraction Data; Bruker AXS Gmbh: Karlsruhe, Germany. (26) Jacoboni, C.; De Pape, R.; Poulain, M.; Le Marouille, J. Y.; Grandjean, D. Acta Crystallogr., Sect. B: Struct. Crystallogr. Cryst. Chem. 1974, 30, 2688. (27) Tressaud, A.; Soubeyroux, J. L.; Dance, J. M.; Sabatier, R.; Hagenmuller, P.; Wanklyn, B. M. Solid State Commun. 1981, 37, 479. (28) Cheetham, A. K.; Thomas, D. M. J. Solid State Chem. 1987, 71, 61. (29) Kovba, L. M.; Lykova, L. N.; Balashov, V. L.; Kharlanov, A. L. Koord. Khim. 1985, 11, 1426. (30) Shevchenko, N. N.; Lykova, L. N.; Kovba, L. M. Zh. Neorg. Khim. 1974, 19, 971. (31) Bramnik, K. G.; Ehrenberg, H.; Fuess, H. J. Solid State Chem. 2001, 160, 45. (32) Shi, Y.; Guo, Y.; Shirako, Y.; Yi, W.; Wang, X.; Belik, A. A.; Matsushita, Y.; Feng, H. L.; Tsujimoto, Y.; Arai, M.; Wang, N.; Akaogi, M.; Yamaura, K. J. Am. Chem. Soc. 2013, 135, 16507.

Thermogravimetric analysis (TGA) curve and table of atomic coordinates and isotropic thermal displacement parameters for Sr2OsO5 and Sr7Os4O19 (PDF)

AUTHOR INFORMATION

Corresponding Author

*E-mail: [email protected]. Notes

The authors declare no competing financial interest.

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REFERENCES

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DOI: 10.1021/acs.inorgchem.6b01354 Inorg. Chem. XXXX, XXX, XXX−XXX