
TY  - JOUR
A1  - Reynolds, Philip A. 
A1  - Figgis, Brian N. 
A1  - Sobolev, Alexander N. 
T1  - The Crystal Structures at 10 K of the Trigonal Salts 
KM<emph type="7">III</emph>(NH<emph tye="8">3</emph>)<emph tye="8">6</emph>(ClO<emph tye="8">4</emph>)<emph tye="8">2</emph>Cl<emph tye="8">2</emph>, M<emph type="7">III</emph> = Os and Cr, and the Possibility of Phase Transitions
JF  - Australian Journal of Chemistry
JO  - Aust. J. Chem.
Y1  - 1999
VL  - 52
IS  - 3
SP  - 219
EP  - 226
KW  - 
UR  - https://doi.org/10.1071/C98077 
N2  - The crystal structures of KOs(NH3)3(ClO4)2Cl2 and KCr(NH3)6(ClO4)2Cl2 were determined at 10 K by X-ray diffraction, and for the osmium salt also at 293 K. At 293 K the osmium salt is trigonal, space group R 3m, with the same simple structure as others of this class of double salt. At 10 K, in agreement with previous radius ratio predictions, both crystals are best described as remaining R 3m. All previously studied members, with larger alkali metal cations, are twinned R 3 at low temperatures, with small, symmetry-breaking rotations of the hexaamminemetal(III) and perchlorate ions about the threefold axis. Differential scanning calorimetry on CsRu(NH3)6(ClO4)2Cl2 suggests that the R 3m to R 3 change is very extended in temperature with only a small discontinuity at the transition temperature. 
ER  -

