The lattice parameters of K 2SnCl 6 at low temperatures determined by high resolution single crystal X-ray diffraction

Abstract

The temperature dependence of lattice parameters of K 2SnCl 6 was measured in the temperature range 300 K>T>240 K by means of high resolution single crystal X-ray diffraction experiments. The cubic phase ( a=9.986(2) A ̊ , Z=4, T=280 K ) was confirmed, whereas in disagreement to earlier authors the intermediate phase was proved to be orthorhombic ( a=9.966(2) A ̊ , ( b=9.948(2) A ̊ , c=10.002(2) A ̊ , Z=4, T=258 K ), and the monoclinic phase to have another unit cell ( a=9.951(2) A ̊ , b=9.948(2) A ̊ , c=10.005(2) A ̊ , β=90.099°, Z=4, T=250 K ). In a small temperature range between the cubic and the orthorhombic phase reflexion splittings and the occurence of superstructure reflexions indicate a further intermediate phase.