A Raman spectroscopic study of the arsenate mineral chenevixite Cu2Fe2(3+)(AsO4)2(OH)4⋅H2O

Ray L Frost; Andrés López; Ricardo Scholz; Cristiano Lana; Yunfei Xi

doi:10.1016/j.saa.2014.06.091

A Raman spectroscopic study of the arsenate mineral chenevixite Cu2Fe2(3+)(AsO4)2(OH)4⋅H2O

Spectrochim Acta A Mol Biomol Spectrosc. 2015 Jan 25:135:192-7. doi: 10.1016/j.saa.2014.06.091. Epub 2014 Jul 5.

Authors

Ray L Frost¹, Andrés López², Ricardo Scholz³, Cristiano Lana³, Yunfei Xi²

Affiliations

¹ School of Chemistry, Physics and Mechanical Engineering, Science and Engineering Faculty, Queensland University of Technology, GPO Box 2434, Brisbane, Queensland 4001, Australia. Electronic address: r.frost@qut.edu.au.
² School of Chemistry, Physics and Mechanical Engineering, Science and Engineering Faculty, Queensland University of Technology, GPO Box 2434, Brisbane, Queensland 4001, Australia.
³ Geology Department, School of Mines, Federal University of Ouro Preto, Campus Morro do Cruzeiro, Ouro Preto, MG 35,400-00, Brazil.

PMID: 25064502
DOI: 10.1016/j.saa.2014.06.091

Abstract

We have studied the mineral chenevixite from Manto Cuba Mine, San Pedro de Cachiyuyo District, Inca de Oro, Chañaral Province, Atacama Region, Chile, using a combination of scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDX) and vibrational spectroscopy. Qualitative chemical analysis shows a homogeneous composition, with predominance of As, Fe, Al, Cu, Fe and Cu. Minor amounts of Si were also observed. Raman spectroscopy complimented with infrared spectroscopy has been used to assess the molecular structure of the arsenate minerals chenevixite. Characteristic Raman and infrared bands of the (AsO4)(3-) stretching and bending vibrations are identified and described. The observation of multiple bands in the (AsO4)(3-) bending region offers support for the loss of symmetry of the arsenate anion in the structure of chenevixite. Raman bands attributable to the OH stretching vibrations of water and hydroxyl units were analysed. Estimates of the hydrogen bond distances were made based upon the OH stretching wavenumbers.

Keywords: Arsenate; Chenevixite; Infrared spectroscopy; Luetheite; Raman spectroscopy.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Arsenates / chemistry*
Electrons
Minerals / chemistry*
Spectrometry, X-Ray Emission
Spectrophotometry, Infrared
Spectrum Analysis, Raman*
Vibration

Substances

Arsenates
Minerals
chenevixite
arsenic acid