Cations Cu(ligand)2+6 doped in lattices of non-cubic Zn(ligand)6(anion)2 are shown to have ESR powder spectra, corresponding with two types of cations, distorted octahedral and regular octahedral. Upon lowering of the temperature the number of distorted molecules increases. Despite of the non-cubic symmetry the results are essentially similar to single crystal observations and investigations on cubic lattices.
Nieuwenhuijse, B., & Reedijk, J. (1973). Jahn-teller distortions in copper(II) complexes as determined from ESR powder spectra. Chemical physics letters, 22(1), 201-203. https://doi.org/10.1016/0009-2614(73)80570-6