title: Assessment of the molecular structure of the borate mineral boracite Mg3B7O13Cl using vibrational spectroscopy.
abstract: Boracite is a magnesium borate mineral with formula: Mg(3)B(7)O(13)Cl and occurs as blue green, colorless, gray, yellow to white crystals in the orthorhombic - pyramidal crystal system. An intense Raman band at 1009 cm(-1) was assigned to the BO stretching vibration of the B(7)O(13) units. Raman bands at 1121, 1136, 1143 cm(-1) are attributed to the in-plane bending vibrations of trigonal boron. Four sharp Raman bands observed at 415, 494, 621 and 671 cm(-1) are simply defined as trigonal and tetrahedral borate bending modes. The Raman spectrum clearly shows intense Raman bands at 3405 and 3494 cm(-1), thus indicating that some Cl anions have been replaced with OH units. The molecular structure of a natural boracite has been assessed by using vibrational spectroscopy.
authors.affiliation: School of Chemistry, Physics and Mechanical Engineering, Science and Engineering Faculty, Queensland University of Technology, G.P.O. Box 2434, Brisbane, Queensland 4001, Australia. r.frost@qut.edu.au
authors.forename: Ray L
authors.initials: RL
authors.lastname: Frost
authors.forename: Yunfei
authors.initials: Y
authors.lastname: Xi
authors.forename: Ricardo
authors.initials: R
authors.lastname: Scholz
mesh_terms: D001881:Borates / Q000737:chemistry*; D008903:Minerals / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D013059:Spectrum Analysis, Raman; D014732:Vibration
chemical_list: D001881:Borates; D008903:Minerals