Determination of the temperature variation of the crystal structure of CdCl2from the EPR data for Mn2+

The d-orbit theory and high-order expressions for the zero-field splitting in trigonal symmetry are used to analyse the temperature variation of the crystal structure of CdCl2 using the experimental EPR data for Mn2+:CdCl2 at different temperatures. The dimension c of the hexagonal unit cell varies linearly with temperature at different rates below and above T0=375+or-10K at which the structure forms a regular octahedron. An accurate value u=0.2435(2) is obtained, which is consistent with the observed value u=0.25(1). Further accurate X-ray measurements are required for testing the results obtained.