Synthesis of Vanadate and Arsenate Spodiosites and Interpretation of Optical Spectra of Manganese‐Doped Sr2VO4C1

New vanadate and arsenate analogs of spodiosite (Sr2-(VO4)C1 and Sr2(AsO4)C1) were prepared. Isomorphism between chromium and vanadium spodiosites was established by formation of complete solid solutions. The vanadate analogs of calcium and barium, the arsenate analog of calcium, phosphate analogs of strontium and barium, and the fluorine analogs, Ca3(VO4)2·CaF2 and Sr3(VO4)2·SrF2, could not be synthesized. The optical absorption spectra of manganese-doped Sr2(VO4)Cl showed the presence of Mn5+ in the vanadium position, the site symmetry being approximately Td. Three transitions, 3T2(F), 3T1(F), and 1Al(G) at (12,000 and 13,000 cm-1), (16,700 cm-1), and (14,300 cm-1), respectively, were observed from the ground state, 3A2(F). The lower symmetry components were strong enough to split the energy level, 3T2(F). The crystal field parameter Dq and the Racah parameters B and C were calculated to be 1200, 470, and 1927 cm-1, respectively.