Crystal Structure and Luminescence Properties of Silver in AgM(PO3)3 (M=Mg, Zn, Ba) Polyphosphates

The relationships between the crystal structures and the luminescent properties of the AgM(PO3)3 (M=Mg, Zn, Ba) polyphosphates are reported in comparison with those of AgPO3. The structure of the magnesium and zinc phosphates is characterized by long polyphosphates chains connected to infinite chains of [AgO6] and [MO6] polyhedra sharing faces. The basic structural phosphate unit in AgBa(PO3)3 is a P3O9 ring. Silver atoms are located in distorted octahedral sites. Two types of luminescent centers have been observed. The UV emission observed in all these materials is typical of isolated Ag+ ions. The visible emission observed only in the zinc phosphate is probably the result of a silver–zinc association.