The Structure and Luminescent Properties of TlZn (PO3)3

The crystal structure and the luminescent properties of TlZn(PO3)3 are studied with respect to Tl+ stereochemistry. In this polyphosphate the Tl+ ions are located in tunnels created by the zinc polyphosphate network [Zn(PO3)3]. Actually the thallium atoms are found in a disymmetric configuration and bond calculation allows the determination of the coordination number by oxygen: 6. Nevertheless a large Tl-O distance induces a low stereochemical activity of the 6s2 lone pair. The luminescent properties are analyzed in the context of Fukudaʹs model. Thermal variations of excitation and emission spectra can be explained by the small influence of the electron-lattice interaction in agreement with the thallium environment.