Structure and Magnetism of Cs₂KCr(CN)₆ at Very Low Temperatures

Abstract

The structure of the elpasolite Cs₂KCr(CN)₆ has been determined at 7.0 K by neutron diffraction. 877 unique reflections refined to R_w = 0.020, Χ = 1.4. The Cr(CN)₆ unit is close to regular octahedral coordination geometry, with bond lengths of 207.4(4) for Cr-C and 116.6(6) pm for C-N. The C-Cr-C angles average to 90.0(5)º and the Cr-C-N angles to 178.3(1)º. The magnetic susceptibility as a function of temperature and the magnetization as a function of magnetic field strength correspond to the ⁴A_2g ground term perturbed by a small magnetic exchange effect.