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Raman microscopy of some natural pseudo‐alums: halotrichite, apjohnite and wupatkiite, at 298 and 77 K
Author(s) -
Frost Ray L.,
Theo Kloprogge J.,
Williams Peter A.,
Leverett Peter
Publication year - 2000
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 - 10.1002/1097-4555(200012)31:12<1083::aid-jrs647>3.0.co;2-#
Subject(s) - raman spectroscopy , microscopy , materials science , natural (archaeology) , analytical chemistry (journal) , mineralogy , chemistry , geology , optics , environmental chemistry , physics , paleontology
The Raman spectra of some common naturally occurring pseudo‐alums, wupatkiite [CoSO 4 ·Al 2 (SO 4 ) 3 ·22H 2 O], apjohnite [MnSO 4 ·Al 2 (SO 4 ) 3 ·22H 2 O] and halotrichite [FeSO 4 ·Al 2 (SO 4 ) 3 ·22H 2 O] were obtained at 298 and 77 K. Bands were observed at 996 and 990 cm −1 and assigned to the ν 1 ( A g ) SO 4 vibration. A band was observed at 972 cm −1 attributed to the water librational mode. Bands at 1134, 1115, 1085 and 1065 cm −1 were attributed to the antisymmetric stretching vibration ν 3 ( B g ) SO 4 . A single band at 454 cm −1 attributed to the ν 2 ( A g ) SO 4 mode split into three bands at 468, 424 and 390 cm −1 in the 77 K spectrum. The band at 618 cm −1 assigned to the ν 4 ( B g ) SO 4 mode resolved into three bands at 623, 603 and 590 cm −1 at 77 K. The splitting of the bands is attributed to the reduction of symmetry of the sulphate ion due to one sulphate oxygen atom being bonded to the M 2+ cation as a unidenate ion. Copyright © 2000 John Wiley & Sons, Ltd.