Flux crystal growth of a series of calcium rare earth silicate chlorides CaLnSiO4Cl (Ln = Pr, Nd, Sm, Eu, Gd, and Tb): Mixed anion materials with a spodiosite-type structure

A series of calcium rare earth silicate chlorides, CaLnSiO 4 Cl (Ln = Pr, Nd, Sm, Eu, Gd, and Tb), was obtained as single crystals from flux crystal growth. The structures were determined by single crystal X-ray diffraction and were found to be related to the spodiosite /Wagnerite mineral structure, Ca 2 PO 4 F. The obtained compositions are variations of the spodiosite structure that result from two simultaneous elemental substitutions. Replacing one calcium for one rare earth element and the simultaneous replacement of one VO 4 3- or PO 4 3- with one SiO 4 4- . CaEuSiO 4 Cl was found to luminesce, and its photoluminescence spectrum is reported. • New Spodiosite-type mixed anion materials were grown as single crystals • Double substitution, rare earth for Ca and SiO 4 4- for PO 4 3- achieves charge balance • Spodiosite related silicate chlorides were prepared by double substitution