title: A vibrational spectroscopic study of the silicate mineral lomonosovite Na₅Ti₂(Si₂O₇)(PO₄)O₂.
abstract: The mineral lomonosovite has been studied using a combination of scanning electron microscopy with energy dispersive X-ray analysis and vibrational spectroscopy. Qualitative chemical analysis gave Si, P, Na and Ti as the as major elements with small amounts of Mn, Ca, Fe and Al. The mineral lomonosovite has a formula Na₅Ti₂(Si₂O₇)(PO₄)O₂. Raman bands observed at 909, 925 and 939 cm(-1) are associated with phosphate units. Raman bands found at 975, 999, 1070, 1080 and 1084 cm(-1) are attributed to siloxane stretching vibrations. The observation of multiple bands in both the phosphate stretching and bending regions supports the concept that the symmetry of the phosphate anion in the structure of lomonosovite is significantly reduced. Infrared spectroscopy identifies bands in the water stretching and bending regions, thus suggesting that water is involved with the structure of lomonosovite either through adsorption on the surface or by bonding to the phosphate units.
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: Frederick L
authors.initials: FL
authors.lastname: Theiss
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: Leonardo M
authors.initials: LM
authors.lastname: Graça
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
mesh_terms: D008855:Microscopy, Electron, Scanning; D008903:Minerals / Q000032:analysis* / Q000737:chemistry*; D015394:Molecular Structure; D010710:Phosphates / Q000737:chemistry; D012426:Russia; D017640:Silicates / Q000737:chemistry; D013055:Spectrophotometry, Infrared; D013059:Spectrum Analysis, Raman; D014025:Titanium / Q000032:analysis
chemical_list: D008903:Minerals; D010710:Phosphates; D017640:Silicates; D014025:Titanium
keywords: Kola Peninsula; Lomonosovite; Phosphate; Raman spectroscopy; Silicate