Structure, Infrared and Raman spectroscopic studies of new AII(SbV0.50CrIII0.50)(PO4)2 (A = Ba, Sr, Pb) yavapaiite phases

Abstract

Three new A II (Sb 0.5 Cr 0.5 )(PO 4 ) 2 (A II  = Ba, Sr, Pb) yavapaiite phases, abbreviated as [ASbCr], have been successfully synthesized by a conventional solid-state reaction in air atmosphere. Their crystal structures have been investigated by Rietveld analysis from the X-ray powder diffraction method. Results show that Ba(Sb 0.5 Cr 0.5 )(PO 4 ) 2 crystallizes in monoclinic C 2 /m space group (Z = 2) with cell parameters a = 8.140(1) A; b = 5.175(1) A; c = 7.802(1) A and β = 94.387(1)°. Structures of A II (Sb 0.5 Cr 0.5 )(PO 4 ) 2 (A II  = Sr, Pb) compounds are comparable, and both crystallize in a distorted yavapaiite structure with C 2 /c space group (Z = 4). Obtained monoclinic cell parameters are: a = 16.5038(2) A; b = 5.1632(1) A; c = 8.0410(1) A; β = 115.85(1) for [SrSbCr] and a = 16.684(2) A; b = 5.156(1) A c = 8.115(1) A; β = 115.35(1)° for [PbSbCr]. Infrared and Raman spectroscopic study was undertaken to provide information about vibrations bonds within the studied yavapaiite materials.