Inorganic Chemistry
1190 NOTES
metal halide complexes and must be related to a change in structure b e b e e n the two phases.lZ The spectrum of BiCls(so1v) has been interpreted in terms of CSvpyramidal symmetry;g judging from the partial Raman spectrum of BiBr3(solv),this molecule probably possesses CsVsymmetry in solution as well. I t is not difficult to understand why previous Raman and infrared studies failed to uncover the lower solidstate symmetry for BiBra and BiC13. First, the early photographic Raman technique applied to crystalline samples probably lacked the resolution necessary to detect the multiplicity of overlapping bands which can be observed photoelectrically. Based on the reported frequencies, it also appears as though the early workers might mistakenly have been investigating BiCh * HzO, and not anhydrous BiC13. Second, since the polyethylene-matrix method used to obtain the far-infrared spectrum of BiBrs was specifically designed to break down the intermolecular structure of related iodides, it could very well have isolated discrete BiBrs molecules as Tvell. The spectrum so obtained, then, was not that of crystalline BiBra; in fact, 196 cm-I in the infrared spectrum very closely matches 200 cm-I in the Raman spectrum of the methanolic BiBra solution. (12) P. J. Hendra, Spectuochiwz Acta, 23A, 2871 (1967).
.4RGONSE
CONTRIBUTIOA FROM THE CHEMISTRY DIVISIOX, NATIOIVAL LABORATORY, ARGOKNE, I L L I N O I S 60139
The Crystal Structure of Potassium Perbromate’ BY STANLEY SIEGEL,BENJAXINTAKI,A N D EVAK. ~ P P E L M Z A N
Received October 2, 1968
A description of the synthesis of perbromates has been published recently by one of u s 2 The symmetry of KBrOl is orthorhombic with a = 8.930 (4), b = 5.921 (4), and c = 7.488 (4) A. The extinctions are: Okl with k 1 odd and hkO with h odd, which leads to space group C2vg-Pn21a or DZhlG-Pnma. A pycnometric determination of the density gave a value of 3.08 (3) g cmP3. The computed density, based on four molecules in the cell, is 3.07 g cn1+.
+
Experimental Section Crystals of KBr04 were grown by evaporation a t room temperature of a saturated solution of the salt. All symmetry information was deduced from Weisseuberg patterns obtained with each crystal axis serving as a rotation axis, using Cu K n radiation. Cell dimensions and errors were determined from counter and diffractometric data after calibration of the instrumental settings with a sodium chloride crystal. Mo Kn radiation (h(K2) 0.71069 B ) was used for this purpose and in the subsequent collection of diffraction information. A spherical crystal of 0.021-cm diameter was used in the struc(1) Work performed under the auspices of the U. S.Atomic Energy Commission. ( 2 ) E. H. Appelman, J . An7. Chevz. Soc., 90, 1900 (1968).
tural analysis. Intensity data were obtained by counter methods utilizing a single-crystal orienter mounted on a General Electric XRD-5 diffraction unit. One quadrant only was investigated because of the onset of radiation damage. The scattering angle was limited to 28 = 5 0 ° , for line intensities were quite reduced beyond this value. Radiation damage was found to be very pronounced. I n order to limit the exposure time of the crystal to irradiation and thereby reduce the radiation damage, the following data collection procedure was adopted. The iritensities of all reflections hkl within a quadrant were obtained rapidly with balanced filters based on a stationary crystal and counter technique and using 10-sec counting times for each filter. Examination of a number of reflections with a 8-28 scan indicated t h a t the weak maxima, those with intensities less than approximately lVoof the value of the most intense ones, could be evaluated more reliably with the scan technique. Accordingly, data for the weaker reflections lvere obtained by scanning, with a scan interval of 2’ on either side of the Bragg angle and a scanning rate of 2”imin. The intensity distribution was recorded on a chart recorder in order to obtain a visual display of line position, line width, and background and t o permit evaluation of the intensity. Numerical values for the intensities were obtained with a planimeter. 4 diffraction line intensity observed as zero was given a value corresponding t o our estimated lower limit of the measurement of the line above the background noise level of the tracing. The radiation damage was kept t o a minimum by exposing the crystal t o X-rays only long enough to obtain intensity readings. Reflections hOO, OkO, and 001 served as standards, and curves displaying changes in intensities with time vere used to deduce corrections to the intensities for all classes of reflections. Following the data collection, a number of reflections for which intensities had been obtained initially from the fresh nonirradiated crystal were reexamined. It was found t h a t corrections so applied led t o reasonable agreement with the initial values. Spherical absorption corrections were applied based on a linear absorption coefficient of 1 l X . i cm-’. This absorption correction is contained in our data reduction program. Following corrections for radiation damage and absorption, the data were scaled and the Lorentz and polarization corrections were applied in the usual manner. Approximate K and Br positions, found by trial, gave y-coordinate values near I/*, indicating the fourfold special positions of Pnma, 4c, b u t not necessarily eliminating the general positions of P n 2 1 a . ~ Improvement of these trial Coordinates, based on space group Pnma, was obtained with the Busing-MartinLevy “Fortran Crystallographic Least-Squares Program.” In these calculations, the scattering factors for K and Br were taken from ref 4. Two-dimensional Fourier syntheses were then computed with the signs of the coefficients determined from the improved K and Br coordinates. T h e electron density maps showed three sets of peaks corresponding t o the oxygen positions--two in the special fourfold positions and one in the general eightfold position. Refined coordinates for all atoms were obtained by a leastsquares analysis on all atomic positions, using the oxygen-scattering curve reported by T o k ~ n a m i . ~I n this and subsequent analyses, a total of 383 independent reflections was used. T h e final values for the coordinates are given in Table I. T h e conventional R factor for this refinement is 0.076. The coordinates were then subjected to a new refinement based on the space group Pn21a, with no essential improvement in the R factor. W e have therefore chosen space group Pnma as representing the symmetry of KBr04. T h e observed and calculated structure factors based on Pnma are presented in Table 11. (3) “International Tables for Crystallography,” Vol. I, T h e Kynoch Press, Birmingham, England, 1952. (4) “International Tables for Crystallography,” Vol. T I T , T h e Kynoch Press, Birmingham, England, 1962. ( 5 ) M. Tokonami, Acta C Y ~ S 19, ! . , 486 (1965).
Vol. 8,No. 5, Muy 1969
NOTES 1191
TABLE I AND THERMAL PARA METERS^ POSITIONAL Pnma
Atom
Y
X
0.1776 (5) K Br 0.07019 (18) 0 (1) 0 . 2 0 7 (2) 0.914 (2) 0 (2) 0 (3) 0.0811 (10) Sumbers in parentheses figure(s).
h 0 0
k
0 0
b 5
0 0
0 0
0 0 0
0
I 1
I I 0
.
112.1 +b.L
I I
1
6
3 3
3 3 3
.*
4 1
1
5 3
I
I
20..
l2.0
...
1
3
1 1
1
0 0
I
3 1 6
1
I,..
1
11.7
1
I
V.1 lS.0 1.7 10.7 1.1
1 I
1
1 1
I
1 1
I
1 2
I 1 2
1 1 I 1
3 5 3 1 3 3 3
I
2
3 3 3
36.0
:I.*:::
2
-47.1
.0.3
16.9 I?.,
6
10.6
1l.L
w..
1
0
6
0
3
-23.. 31.1
1
1
3
31.1 2,.z 33.1
6
I
I
¶
I I
I I
1 2
I I
21.0 I.. 23.3 16.0
*5
3
3 I
16.0 10.2
L
b
L.2
L
25.1
33.. .L.
s
I
6.5
6.1
I..0 w.1
1 b
e.&
L L
-1.7 -I.*
3 1
1
-11.‘ 3.1 -I., -21.1 81.1 -1J.L
I
1
I
-,,.,
L1.6
I
e
-79.0
. , . ,... .. x 1 .78Fo
0
L b
*Y
I I I
1.6
I.‘ 11.3
2 4
I a I D 1 I 1 1
ll.+
I 0
1 3 1 1
61.7
3:: 2:: 12.0 I..‘
k
0 0 0 0 0
,e.. -,,.*
2 I
L
D
53.0
6,,*
1
0
$0.1
1
0 1 4
0
,,.1
.78Pc -123.8 111.1 -S+.l
2
0
0
101.9
1
0 0 0 0 0
.?8P0
1 0 0 0
9.0 1.9
3 2
7
1. 20.1
1
I
16..
0 0
7
16.6
1
19.0
8
e..
16..
14.0
3
I
0.1
0
0
8.. +l.P
-11.0
1
0
.78Fc 11.7 11.. -*I..
-,L.I
11.0 31.S -20.7 8.0
-1..0 -16.3
ll.0 -2s15.1 ..
-,Lo
1
3
I
1
1
0
L
1.3
0
2
2‘.6
21.0
1
1
1.8
1.0
2..,
1.8 ,,.2
13.0 I...
11.7 -I..,
13.1 1.0
38.9 -97.9 -1.1 11.3
-)I..
13.0 17.3
I
I
3 2 b I I 1
2L.9
-1I.l 3I.L
3a.v 1.0
31.1 -0.1
49.1
-+*.I
71.1 ll.0
11..
...,
45.3
11.3 I..‘ 11.1
17.7 -37.3 -1k.O 32.1
58.6
13..
I.. 6.6
IO..
-11..
r
..+
L1.S -1.9 -10.0
9.9
-a.,
-1+.1
I
3.3
..L.l 4.7
-13.4 i.., -13,.
11.8 15.e
31.7 31.1 11.3
. 1 11.0 1.h
,I..
48.3 10.. 36.1
-18.7
31.5
b1.l
-31.1
-7.5
0
,*..
16.0 -17..
41.0
-33.3
1 0
0 I
21.. 11.7 17.7 20.2
7.0
6 6
I I
11.. *.o -10.1 -11.1
1.7
16.0
-11..
+
IO.‘
10.1
IO..
-8..
-I,.
-10.2
L.1
.78Fc
.78Fo
11.1
I..,
-11.1 L,., 6s. -31.5
1.0 M.1
I..,
0
1
-I.+ -18.3
-21.1 16..
so.*
3
h
1.8 8.6 1.1 20.3 3.7 13.8
-11.1
s1.1
,6.*
¶ ..
a e
0.1623 (6) 2 . 2 7 (8) 0.6847 ( 2 ) 1.59 (4) 0.548 (2) 3 . 1 (3) 0.577 (2) 3 . 7 (3) 0.809 (1) 3 . 2 ( 2 ) deviations in the last
TABLE I1 OBSERVED AND CALCULATED STRUCTURE FACTORS
93.8 1.0 b1.6 27.1
...I
B,
2
0.25 0.25 0.25 0.25 0.0277 (17) are standard
1-0 distances in the periodate i ~ n . ~The - ~ oxygenoxygen distances within the configuration are: O(2)(2)0(3) = 2.65 (2) A, O(1)-(2)0(3) = 2.61 ( 2 ) if)O(1)O(2) = 2.63 (2) A, and O(3)-0(3) = 2.63 (2) if. The corresponding bond angles are : 0 (1)BrO (3) = 108” 48’, 0(2)Br0(3) = 110’ 12’, O(l)Br0(2) = 110’ ll’, and 0(3)Br0(3) = 108” 50’. Eight K-0 distances are observed with contacts less than 3.08 as shown in Table 111. The average weighted K-0 distance is 2.92
Y7.1 59..
-3.1
11.1 I.,
I..
11..
2q.. 22.5
23.9
IO.,
30.9
13.3 3S.I
-17.8 iQ.2
11.1
l
2.1 1.0
k
,.e
0 0
.. .,
11.1
-11.5 -5.9
I...
0
0
..‘
-10.1
I
I..)
2.1 10.1
14.8 42..
16.. 33.0
,,.* I..,
10.1 31.2
6
s.,
21
Jl.1 5.1
1.7 25.9
Results
TABLE HIa BONDDISTANCES (A) Br-O(1) 1 . 5 9 3 (14) O(3)-0(3) Br-O(2) 1.614 (16) K-O(2’) K-(2)0(3”’) Br-(2)0(3) 1.617 (10) 0(2)-(2)0(3) 2 . 6 5 (2) K-O(1) 0(1)-(2)0(3) 2 . 6 1 (2) K-(2)0(3) 0(1)-0(2) 2 . 6 3 (2) K-(2)0(3”) a Numbers in parentheses are standard deviations figure (s).
2 . 6 3 (2) 2 . 7 7 (2) 2 . 9 3 (1) 2 . 9 0 (2) 3 . 0 8 (1) 2 . 8 4 (1) in the last
The Br04- configuration is tetrahedral with BrO(1) = 1.593 (14) if, Br-0(2) = 1.614 (16) A, and Br-(2)0(3) = 1.617(10) if. Within error, the bond distances are equal, leading to an average value of 1.610 if. This may be compared with values of 1.44-1.46 if for (21-0 distances in the perchlorate ion and 1.79 A for (6) R . W. G. Wyckoff, “Crystal Structures,” Vol. 3, Interscience Puh‘ishers, New York, N. P., 1Y65, p 45.
3.L
16.9
2L.l
2.0 29..
o I
3.q I., 6.0
16.0 19.9
,
..9 6..
9.1
18.7
1
4.5
8.1 1.9 11.0
>a.e
I
7.6
13.2
27.1
1
KBr04 belongs to the Bas04 structure type and is therefore isostructural with several perchlorates reported in the literature.6 Bond distances for KBrOl were computed with the Busing-Martin-Levy “Fortran Crystallographic Function and Error Program” and are shown in Table 111.
11.1
6.2
1.3 29.1
63..
...1-
*I..
17.1 15.2 31.I I1.J 1.1 11.3
3l
IO..
5.6
LP.,
1.8
l*.O
-16.7
14.6
3.6 41.1
l.s
28.9
1
I
1.1
-11.1
.76F.
7.6
49.0
26.9 33.0
11.4
1
-20.6
,..I
.78F.
26.2
L I
I 0 I1
lP.O 19.1
47.1 6.6
3
h
J.h
I,..
*,,6
21.9 I(.*
8.7 4.3 6.9 2.0
0 I
9..
11.3 10.5
L
-21.1 -17.7
33.,
31.3 1L.I 8.1 10.0 I,.. 11.1 18.3
.78F,
k L ¶
63.2 I.,
4..
2.0 1.1
1.9 20.7
I,.0 2,.D 20.1 8.7
11.9 8.8 24.0
18.3 2.0 J6.l
2.L 8.9
18.9 1.5 >.L 2 6.9 12.3
if, corresponding essentially to the ionic radii sum corrected for the eightfold coordination.m (7) M . R. Truter, D. W. J. Cruickshank, and G. A. Jeffery, A c t a Cvyst.,
13, 855 (1960). ( 8 ) H. G. Smith and H. A. Levy, ibid., 15, 1201 (1962).
(9) A. F. Wells, “Structural Inorganic Chemistry,” Oxford University Press, London, 1962, p p 334, 335. (10) G. T. Seaborg and J. J . Katz, “ T h e Actinide Elements,” McGrawHill Book Co., Inc., New York, N. Y., 1954, p 775.
CONTRIBUTION FROM THE DEPARTMENT OF CHEXISTRY, UNIVERSITY OF ARKANSAS,FAYETTEVILLE, ARKANSAS 72701
Coordination Chemistry of Phosphoryl Compounds. 111. Transition Metal Complexes of Trimorpholinophosphine Oxidel BY J. T. DONOGHUE, E. FERNANDEZ,~ AND D. A . PETERS3
Received November 11 1968
In a set of earlier papers, the coordination chemistry of hexamethylphosphoramide, [ (CH&N]sPO, was reThis ligand, found to be an oxygen donor in (1) P a r t 11: J . Inorg. Nucl. Chem., in press. (2) NSF Summer Undergraduate Research Participant. (3) Undergraduate Research Participant. (4) J. T. Donoghue and R. S. Drago, Inovg. Chem., 1, 866 (1962). ( 5 ) J. T. Donoghue and R. S. Drago, ibid., 2, 572 (1963). (6) J. T . Donoghue and I
