title: Structure of Mg2.56V1.12W0.88O8 and vibrational raman spectra of Mg2.5VWO8 and Mg2.5VMoO8.
abstract: Mg(2.56)V(1.12)W(0.88)O(8) crystals were grown from a MgO/V(2)O(5)/WO(3) melt. X-ray single-crystal diffraction studies revealed that it is orthorhombic with space group Pnma, a = 5.0658(5) A, b = 10.333(1) A, c = 17.421(2) A, Z = 6, and is isostructural with Mg(2.5)VMoO(8). Raman spectra are reported, and the assignment of the Raman bands is made by comparing the metal-oxygen vibrations of VO(4)/WO(4) tetrahedra in Mg(2.5)VWO(8) with the metal-oxygen vibrations of VO(4)/MoO(4) tetrahedra in Mg(2.5)VMoO(8). The stretching vibrations appearing at 1016 and 1035 cm(-)(1) are assigned to Mo=O and W=O double bonds, respectively, associated with the Mg(2+) cation vacancies.
authors.affiliation: Department of Chemistry, Northwestern University, Evanston, IL 60208, USA.
authors.forename: Jason D
authors.initials: JD
authors.lastname: Pless
authors.forename: Hack-Sung
authors.initials: HS
authors.lastname: Kim
authors.forename: Jared P
authors.initials: JP
authors.lastname: Smit
authors.forename: Xiandong
authors.initials: X
authors.lastname: Wang
authors.forename: Peter C
authors.initials: PC
authors.lastname: Stair
authors.forename: Kenneth R
authors.initials: KR
authors.lastname: Poeppelmeier