Structure and luminescence of some CsLnW2O8 compounds

Abstract

The structure of CsLuW2O8 was determined from single-crystal X-ray diffraction data with a = 9.322(3), B = 5.132(6), C = 7.277(4) Å, and β = 95.66(4)°, in the space group P2/c. It is composed of double chains of distorted WO6 octahedra that share an edge across the chain and share opposite corners along the chain in the c direction. The tungsten-oxygen chains are interconnected via the lutetium and cesium atoms which are in eight- and twelve-coordination with oxygen. A comparison with the related structure of KYW2O8 is made. The compounds CsLnW2O8 (Ln = Y, Gd) have a similar structure. The three tungstates (Ln = Y, Gd, Lu) exhibit an intense luminescence at room temperature, whereas KYW2O8 does not luminesce at all. The luminescence of the compounds with Ln = Eu, Tb are also reported.