title: An SEM-EDX and Raman spectroscopic study of the fibrous arsenate mineral liskeardite and in comparison with other arsenates kaňkite, scorodite and yvonite.
abstract: The mineral liskeardite, an arsenate mineral with major cations of iron and aluminium, has been studied by a combination of scanning electron microscopy with energy dispersive spectroscopy and Raman spectroscopy. The mineral shows a fibrous nature. Semi-quantitative chemical analysis shows an Al and Fe arsenate phase with minor amounts of K, Cu, S and Si. Scanning electron microscopy shows a fibrous material. Intense Raman bands at 893, 867 and 843 cm(-1) are assigned to the ν1 and ν3 AsO4(3)(-) and HOAsO3(2)(-) symmetric and antisymmetric stretching vibrations. Raman bands are observed at 514, 499, 485 and 477 cm(-1) and are assigned to the ν4 out of plane bending modes of the AsO4(3)(-) and HOAsO3(2)(-) units. The series of bands at 373, 356 and 343 cm(-1) are assigned to the ν2 symmetric bending modes. Two groups of OH stretching bands are observed and assigned to OH unit and water stretching vibrations. A comparison of the Raman spectrum of liskeardite with scorodite, kaňkite and yvonite is made.
authors.affiliation: 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.
authors.forename: Ray L
authors.initials: RL
authors.lastname: Frost
authors.affiliation: Geology Department, School of Mines, Federal University of Ouro Preto, Campus Morro do Cruzeiro, Ouro Preto, MG 35,400-00, Brazil.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Scholz
authors.affiliation: Institute of Geological Engineering, Faculty of Mining and Geology, VŠB - Technical University of Ostrava, 17. listopadu 15/2172, 708 33 Ostrava-Poruba, Czech Republic.
authors.forename: Jakub
authors.initials: J
authors.lastname: Jirásek
authors.affiliation: Federal University of Itajubá (UNIFEI), Campus Itabira, Itabira, Minas Gerais, Brazil.
authors.forename: Fernanda Maria
authors.initials: FM
authors.lastname: Belotti
keywords: Arsenate; Infrared spectroscopy; Kaňkite; Liskeardite; Raman spectroscopy; Scorodite; Yvonite