title: A Raman spectroscopic study of the basic carbonate mineral callaghanite Cu2Mg2(CO3)(OH)6·2H2O.
abstract: Raman spectrum of callaghanite, Cu2Mg2(CO3)(OH)6·2H2O, was studied and compared with published Raman spectra of azurite, malachite and hydromagnesite. Stretching and bending vibrations of carbonate and hydroxyl units and water molecules were tentatively assigned. Approximate O-H…O hydrogen bond lengths were inferred from the spectra. Because of the high content of hydroxyl ions in the crystal structure in comparison with low content of carbonate units, callaghanite should be better classified as a carbonatohydroxide than a hydroxycarbonate.
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: Jiří
authors.initials: J
authors.lastname: Čejka
authors.forename: Jiří
authors.initials: J
authors.lastname: Sejkora
authors.forename: Ivana
authors.initials: I
authors.lastname: Jebavá
authors.forename: Yunfei
authors.initials: Y
authors.lastname: Xi
authors.forename: Sara J
authors.initials: SJ
authors.lastname: Couperthwaite
authors.forename: Ray L
authors.initials: RL
authors.lastname: Frost
mesh_terms: D002254:Carbonates / Q000737:chemistry*; D018360:Crystallography, X-Ray; D008903:Minerals / Q000737:chemistry*; D013059:Spectrum Analysis, Raman; D014732:Vibration
chemical_list: D002254:Carbonates; D008903:Minerals