A Raman and Infrared Spectroscopic Study of the Phosphate Mineral Pseudolaueite and in Comparison with Strunzite and Ferrostrunzite

Abstract

The Raman spectra of pseudolaueite, strunzite, ferrostrunzite and ferristrunzite have been obtained at 298 K using Raman microscopy. These spectra are compared with their infrared spectra. The vibrational spectra of the four minerals are different, in line with differences in crystal structure and composition. Some similarity in the Raman spectra of the hydroxyl-stretching region exists, particularly but characteristic differences in the OH deformation regions are observed. Differences are also observed in the phosphate stretching and deformation regions. Graphical Abstract This paper offers new knowledge and understanding of the mineral pseudolaueite of formula Mn 2? Fe 2 3? (PO 4 ) 2 (OH) 2 Á8H 2 O,a hydrated hydroxy phosphate of ferric iron and manganese.

Ferraioloite from the Sítio do Castelo mine, Folgosinho (Guarda, Portugal), description and Raman spectroscopy

“…The band assignment in this spectral region is not entirely clear. For example, an intense band at 215 cm -1 observed in the bobierrite pattern is attributed to the Mg-O stretching vibration (Frost et al 2002), and conversely, bands below 249 cm -1 in pseudolaueite are considered to be lattice modes (Frost et al 2015). Alves et al (2012) pointed out the similarity of the phosphate occurrence in the Sítio do Castelo mine with those at the Krásno deposit in the Czech Republic (Sej kora et al 2006).…”