title: Vibrational spectroscopy of the mineral meyerhofferite CaB3O3(OH)5·H2O--an assessment of the molecular structure.
abstract: Meyerhofferite is a calcium hydrated borate mineral with ideal formula: CaB3O3(OH)5·H2O and occurs as white complex acicular to crude crystals with length up to ~4 cm, in fibrous divergent, radiating aggregates or reticulated and is often found in sedimentary or lake-bed borate deposits. The Raman spectrum of meyerhofferite is dominated by intense sharp band at 880 cm(-1) assigned to the symmetric stretching mode of trigonal boron. Broad Raman bands at 1046, 1110, 1135 and 1201 cm(-1) are attributed to BOH in-plane bending modes. Raman bands in the 900-1000 cm(-1) spectral region are assigned to the antisymmetric stretching of tetrahedral boron. Distinct OH stretching Raman bands are observed at 3400, 3483 and 3608 cm(-1). The mineral meyerhofferite has a distinct Raman spectrum which is different from the spectrum of other borate minerals, making Raman spectroscopy a very useful tool for the detection of meyerhofferite in sedimentary and lake bed deposits.
authors.affiliation: School of Chemistry, Physics and Mechanical Engineering, Science and Engineering Faculty, Queensland University of Technology, Brisbane, Queensland 4001, Australia. r.frost@qut.edu.au
authors.forename: Ray L
authors.initials: RL
authors.lastname: Frost
authors.forename: Andrés
authors.initials: A
authors.lastname: López
authors.forename: Yunfei
authors.initials: Y
authors.lastname: Xi
authors.forename: Ricardo
authors.initials: R
authors.lastname: Scholz
authors.forename: Geraldo Magela
authors.initials: GM
authors.lastname: da Costa
authors.forename: Fernanda M
authors.initials: FM
authors.lastname: Belotti
authors.forename: Rosa Malena Fernandes
authors.initials: RM
authors.lastname: Lima
mesh_terms: D001881:Borates / Q000737:chemistry*; D017610:Calcium Compounds / Q000737:chemistry*; D008903:Minerals / Q000737:chemistry*; D013055:Spectrophotometry, Infrared; D013059:Spectrum Analysis, Raman; D014867:Water / Q000737:chemistry; D014961:X-Ray Diffraction
chemical_list: D001881:Borates; D017610:Calcium Compounds; D008903:Minerals; D014867:Water; C031316:calcium borate
keywords: Borate; Colemanite; Inyoite; Meyerhofferite; Raman spectroscopy