A vibrational spectroscopic study of hydrated Fe3+ hydroxyl-sulfates; polymorphic minerals butlerite and parabutlerite

作者：Cejka Jiri; Sejkora Jiri; Plasil Jakub; Bahfenne Silmarilly; Palmer Sara J; Frost Ray L^*

来源：Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy , 2011, 79(5): 1356-1363.

DOI：10.1016/j.saa.2011.04.069

• Butlerite
• Parabutlerite
• Iron(III) sulfates
• Raman spectroscopy
• Infrared spectroscopy
• Hydroxyl ions
• Molecular water
• Hydrogen bonds

Raman and infrared spectra of two polymorphous minerals with the chemical formula Fe3+(SO4)(OH)center dot 2H(2)O, monoclinic butlerite and orthorhombic parabutlerite, are studied and the spectra assigned. Observed bands are attributed to the (SO4)(2-) stretching and bending vibrations, hydrogen bonded water molecules, stretching and bending vibrations of hydroxyl ions, water librational modes, Fe-O and Fe-OH stretching vibrations, Fe-OH bending vibrations and lattice vibrations. The O-H center dot center dot center dot O hydrogen bond lengths in the structures of both minerals are calculated from the wavenumbers of the stretching vibrations. One symmetrically distinct (SO4)(2-) unit in the structure of butlerite and two symmetrically distinct (SO4)(2-) units in the structure of parabutlerite are inferred from the Raman and infrared spectra. This conclusion agrees with the published crystal structures of both mineral phases.

• 出版日期2011-9