Premium
Single‐crystal Raman spectroscopy of natural finnemanite and comparison with its synthesised analogue
Author(s) -
Bahfenne Silmarilly,
Rintoul Llew,
Langhof Jörgen,
Frost Ray L.
Publication year - 2011
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/jrs.2973
Subject(s) - raman spectroscopy , arsenite , chemistry , crystal (programming language) , spectral line , crystallography , single crystal , crystal structure , analytical chemistry (journal) , physics , arsenic , optics , organic chemistry , chromatography , astronomy , computer science , programming language
The single‐crystal Raman spectra of the natural mineral finnemanite Pb 5 (AsO 3 ) 3 Cl • from the Långban locality, Filipstad district, Värmland province, Sweden, are presented for the first time. It is a hexagonal mineral belonging to the ortho ‐arsenite group, where the [AsO 3 ] 3− ion is isolated. The spectra of finnemanite are characterised by a strong band at 734 cm −1 overlying a shoulder at 726 cm −1 , and broad overlapping bands in the lower wavenumber region with the strongest band positioned at 174 cm −1 . Band assignments were made on the basis of band symmetry, experimental band positions from the literature, the calculated Raman spectrum using density functional theory and spectral comparison with other ortho ‐arsenite minerals reinerite, cafarsite and nealite as well as with synthetic lead arsenite compounds Pb 2 (AsO 2 ) 3 Cl, Pb 2 As 2 O 5 and PbAs 2 O 4 . The band at 734 cm −1 was assigned to ν 1 (AsO 3 ); those at 726 and 640 cm −1 to ν 3 ; those at 372 and 357 cm −1 to ν 2 , and those at 244, 239 and 207 cm −1 to ν 4 . The single‐crystal spectra of finnemanite showed good mode separation, allowing the bands to be assigned to the symmetry species A g , E 1g or E 2g . Copyright © 2011 John Wiley & Sons, Ltd.