THE STRUCTURE OF SR2(VO4)CL AND SR2(CRO4)CL AND SPECTROSCOPIC PROPERTIES OF MN(5+)- AND CR(5+)-DOPED SR2(VO4)CL

The structures of the spodiosite-type compounds Sr2(MVO4)Cl [M = V, Cr] and the spectroscopic properties (EPR, ligand field) of Mn5+ - and Cr5+-doped Sr2(VO4)Cl [3A2 and 2E ground states in Td, respectively] are reported. Evidence is presented that Cr5+ undergoes vibronic coupling effects of the Jahn-Teller type. Paramagnetic probe cations will only reflect the geometry of a host site, if they possess nondegenerate ground states in the respective symmetry and if their ionic radii are comparable to those of the host cations. © 1993 Academic Press, Inc.