Raman spectroscopy of hydrogen-arsenate group (AsO3OH) in solid-state compounds: cobalt mineral phase burgessite Co2(H2O)4[AsO3OH] 2•H2O

Raman spectrum of burgessite, Co-2(H2O)(4)[AsO3OH] (2)center dot H2O, was studied, interpreted and compared with its infrared spectrum. The stretching and bending vibrations of (AsO3) and As-OH units, as well as the stretching, bending and libration modes of water molecules and hydroxyl ions were assigned. The range of O-H center dot center dot center dot O hydrogen bond lengths was inferred from the Raman and infrared spectra of burgessite. The presence of (AsO3OH)(2-) units in the crystal structure of burgessite was proved, which is in agreement with its recently solved crystal structure. Raman and infrared spectra of erythrite inferred from the RRUFF database are used for comparison. Copyright (C) 2010 John Wiley & Sons, Ltd.