title: A vibrational spectroscopic study of the arsenate minerals cobaltkoritnigite and koritnigite.
abstract: Raman spectra of two well-defined types of cobaltkoritnigite and koritnigite crystals were recorded and interpreted. Significant differences in the Raman spectra of cobaltkoritnigite and koritnigite were observed. Observed Raman bands were attributed to the (AsO3OH)(2-) stretching and bending vibrations, stretching and bending vibrations of water molecules and hydroxyl ions. Both Raman and infrared spectra of cobaltkoritnigite identify bands which are attributable to phosphate and hydrogen phosphate anions proving some substitution of phosphate for arsenate in the structure of cobaltkoritnigite. The O-H⋯O hydrogen bond lengths in the crystal structure of koritnigite were inferred from the Raman spectra and compared with those derived from the X-ray single crystal refinement. The presence of (AsO3OH)(2-) units in the crystal structure of cobaltkoritnigite and koritnigite was proved from the Raman spectra which supports the conclusions of the X-ray structure analysis.
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: School of Chemistry, Physics and Mechanical Engineering, Science and Engineering Faculty, Queensland University of Technology, GPO Box 2434, Brisbane, Queensland 4001, Australia.
authors.forename: Andrés
authors.initials: A
authors.lastname: López
authors.affiliation: School of Chemistry, Physics and Mechanical Engineering, Science and Engineering Faculty, Queensland University of Technology, GPO Box 2434, Brisbane, Queensland 4001, Australia.
authors.forename: Yunfei
authors.initials: Y
authors.lastname: Xi
authors.affiliation: Geology Department, School of Mines, Federal University of Ouro Preto, Campus Morro do Cruzeiro, Ouro Preto, MG 35400-00, Brazil.
authors.forename: Cristiano
authors.initials: C
authors.lastname: Lana
authors.affiliation: Mining Engineering Department, School of Mines, Federal University of Ouro Preto, Campus Morro do Cruzeiro, Ouro Preto, MG 35400-00, Brazil.
authors.forename: Larissa
authors.initials: L
authors.lastname: Souza
authors.affiliation: Geology Department, School of Mines, Federal University of Ouro Preto, Campus Morro do Cruzeiro, Ouro Preto, MG 35400-00, Brazil.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Scholz
authors.affiliation: Department of Mineralogy and Petrology, National Museum, Cirkusová 1740, CZ-193 00, Praha 9, Czech Republic.
authors.forename: Jiří
authors.initials: J
authors.lastname: Sejkora
authors.affiliation: School of Chemistry, Physics and Mechanical Engineering, Science and Engineering Faculty, Queensland University of Technology, GPO Box 2434, Brisbane, Queensland 4001, Australia; Department of Mineralogy and Petrology, National Museum, Cirkusová 1740, CZ-193 00, Praha 9, Czech Republic.
authors.forename: Jiří
authors.initials: J
authors.lastname: Čejka
mesh_terms: D001149:Arsenates / Q000737:chemistry*; D003035:Cobalt / Q000737:chemistry*; D008903:Minerals / Q000737:chemistry*; D013059:Spectrum Analysis, Raman; D014732:Vibration
chemical_list: D001149:Arsenates; D008903:Minerals; D003035:Cobalt; C025657:arsenic acid
keywords: Cobaltkoritnigite; Hydrogen bonds; Hydrogen-arsenate; Koritnigite; Molecular water; Raman spectroscopy