title: Spectroscopic characterisation of the LDH mineral quintinite Mg4Al2(OH)12CO3·3H2O.
abstract: Raman and infrared spectroscopy coupled with scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX) have been applied to study the natural hydrotalcite quintinite Mg4Al2(OH)12[CO3]·3H2O. SEM shows the mineral to be a homogenous phase. Quintinite is composed of Mg and Al as the major elements with minor amounts of Fe. Two Raman bands at 1046 and 1062 cm are assigned to the ν1 symmetric stretching modes of the carbonate anion. Thermal treatment shifts these bands to higher wavenumbers indicating a change in the carbonate bonding. Hydrogen bond distances are calculated using a Libowitzky-type empirical function and varied between 2.61 and 3.00 Å. Stronger hydrogen bonds were formed by water units as compared to the hydroxyl 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.
authors.forename: Frederick
authors.initials: F
authors.lastname: Theiss
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. 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
keywords: Carbonate; Infrared spectroscopy; Quintinite; Raman spectroscopy