Polarized infra-red and Raman spectra of monoclinic α-KLn(WO 4) 2 single crystals (Ln = Sm—Lu, Y)

Abstract

The polarized i.r. and Raman spectra for single crystals of α-KLn(WO 4) 2 family were measured, where Ln = Y and lanthanides from Sm to Lu. The molecular and crystal structures were analysed in terms of C 2/ c = C 6 2 h (Z = 4) monoclinic unit cell. A comparison of vibrational spectra measured for isomorphic crystals of several RE elements was used to describe the internal and external optic modes. On that basis the hexacoordination of tungsten atoms and polymeric (W 2O 10) n clusters with ▪ and ▪ bridge systems were discussed.