Raman spectroscopy of the molybdate minerals chillagite (tungsteinian wulfenite‐I4), stolzite, scheelite, wolframite and wulfenite

Abstract

Raman spectra of chillagite, wulfenite, stolzite, scheelite and wolframite were obtained at 298 and 77 K using a Raman microprobe in combination with a thermal stage. Chillagite is a solid solution of wulfenite and stolzite. The spectra of these molybdate minerals are orientation dependent. The band at 695 cm −1 is interpreted as an antisymmetric bridging mode associated with the tungstate chain. The bands at 790 and 881 cm −1 are associated with the antisymmetric and symmetric A g modes of terminal WO 2 whereas the origin of the 806 cm −1 band remains unclear. The n 4 .E g / band was absent for scheelite. The bands at 353 and 401 cm −1 are assigned as either deformation modes or as r(B g ) and d.A g / modes of terminal WO 2 . The band at 462cm −1 has an equivalent band in the infrared at 455 cm −1 assigned as d as .A u / of the .W 2 O 4 / n chain. The band at 508 cm −1 is assigned as n sym .B g / of the .W 2 O 4 / n chain.

A combined theoretical and experimental study of electronic structure and optical properties of β-ZnMoO4 microcrystals

“…According to the group theory calculations and symmetry [56][57][58], molybdate and tungstate crystals with a wolframite-type monoclinic structure present 3N = 36 degrees of freedom. Therefore, there are N = 12 atoms within the unit monoclinic cell as illustrated previously (see Figures 3(a,b)).…”

Raman spectroscopic study of the basic copper sulphates—implications for copper corrosion and ‘bronze disease’

“…24 The Raman spectra of the isomorphous series descloizite [PbZn(VO 4 )(OH)] and mottramite [PbCu(VO 4 ) (OH)] were obtained at 298 and 77 K. 25 Raman spectroscopy has also been used to study the mixed anionic mineral chillagite. 26 Further, the molecular structure of some naturally occurring pseudo-alums has been determined. 27,28 Recently, the Raman spectroscopy of the vivianite phosphates and sulphates has been undertaken.…”

Preparation and visible light responsive photocatalytic activity of Fe3O4/Ni-Al-Ce LDH/Bi2WO6 composites

“…For pure Bi 2 WO 6 , the peaks at 600-1000 cm -1 can be assigned to the stretching vibration of W-O. 29 The band at 310 cm -1 can be assigned to translational modes involving the simultaneous motions of Bi 3+ and WO 6 6-. 30 Additionally, the peaks at 700 and 790 cm -1 are interpreted as the antisymmetric bridging mode associated with the tungstate chain and the antisymmetric A g mode of the terminal O-W-O groups, respectively.…”