An X-Ray Crystallographic Study of (Zn, Cd, Mn)3(PO4)2 Compounds

Abstract

<p> The crystal structures of four compounds of the type (Zn,Cd,Mn)3(PO4)2 have been determined by X-ray diffraction methods. These structures are the high temperature (β) phase of Zn3(PO4)2, the related structures of β1-Mn3(PO4)2 and β1-Cd3(PO4)2, and the structure of a member of a solid solution of median composition Zn2Cd(PO4)2 which is similar in structure to the mineral graftonite. The orthophosphates of the small divalent metal ions have been separated into four structure classes and the stability of each of these classes is discussed in terms of cation concentration and the types of cation sites which exist in these structures. The correlation of a host crystal structure and the luminescence of Mn++ when this ion is added as an impurity is also discussed.</p>