title: A vibrational spectroscopic study of the phosphate mineral vantasselite Al4(PO4)3(OH)3·9H2O.
abstract: We have studied the phosphate mineral vantasselite Al₄(PO₄)₃(OH)₃·9H₂O using a combination of SEM with EDX and Raman and infrared spectroscopy. Qualitative chemical analysis shows Al, Fe and P. Raman bands at 1013 and 1027 cm(-1) are assigned to the PO₄(3-)ν₁ symmetric stretching mode. The observation of two bands suggests the non-equivalence of the phosphate units in the vantasselite structure. Raman bands at 1051, 1076 and 1090 cm(-1) are attributed to the PO₄(3-)ν₃ antisymmetric stretching vibration. A comparison is made with the spectroscopy of wardite. Strong infrared bands at 1044, 1078, 1092, 1112, 1133, 1180 and 1210 cm(-1) are attributed to the PO₄(3-)ν₃ antisymmetric stretching mode. Some of these bands may be due to δAl₂OH deformation modes. Vibrational spectroscopy offers a mechanism for the study of the molecular structure of vantasselite.
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: 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
authors.affiliation: Federal University of Itajubá, Campus Itabira, Itabira, MG 35,903-087, Brazil.
authors.forename: Fernanda Maria
authors.initials: FM
authors.lastname: Belotti
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
keywords: EDS; Infrared spectroscopy; Phosphate; Raman spectroscopy; SEM; Vantasselite