• journal_title：Mineralogical Magazine
• Contributor：G. Della Ventura ; G. Ventruti ; F. Bellatreccia ; F. Scordari ; M. Cestelli Guidi
• Publisher：Mineralogical Society of Great Britain and Ireland
• Date：2013-06-01
• Format：text/html
• Language：en
• Identifier：10.1180/minmag.2013.077.4.09
• journal_abbrev：Mineralogical Magazine
• issn：0026-461X
• volume：77
• issue：4
• firstpage：499
• section：Articles

This paper relates an infrared (IR) (6000–2500; 1400–400 cm⁻¹) spectroscopic study of sideronatrite, Na₂Fe³⁺(SO₄)₂(OH)·3H₂O. Spectra in the 600–1250 cm⁻¹ range are dominated by fundamental S–O absorption bands. Factor-group analysis based on the space group P2₁2₁2₁ (formula" id="inline-formula-1">f" /> ) is in accordance with the observed band multiplicity. A broad and convolute absorption centred around 3400 cm⁻¹ and a sharp band at 3605 cm⁻¹ are observed in the 2900–3900 cm⁻¹ frequency region. The resolution of the broad band is significantly improved at liquid nitrogen temperature; seven components can be fitted to the pattern and these can be assigned to H₂O/OH molecules in the structure. All components in the broad band and the sharp absorption at 3605 cm⁻¹ are strongly polarized for E//a, in accordance with the structure analysis results. Infrared transmission spectroscopy is a useful tool to identify these sulfate minerals occurring in specific geological environments.