Infrared and Raman Spectroscopy of Ammoniovoltaite, (NH4)2Fe2+5Fe3+3Al(SO4)12(H2O)18

Abstract

Ammoniovoltaite, (NH4)2Fe2+5Fe3+3Al(SO4)12(H2O)18, is a complex hydrated sulphate of the voltaite group that has been recently discovered on the surface of the Severo-Kambalny geothermal field (Kamchatka, Russia). Vibrational spectroscopy has been applied for characterization of the mineral. Both infrared and Raman spectra of ammoniovoltaite are characterized by an abundance of bands, which corresponds to the diversity of structural fragments and variations of their local symmetry. The infrared spectrum of ammoniovoltaite is similar to that of other voltaite-related compounds. The specific feature related to the dominance of the NH4 group is its ν4 mode observed at 1432 cm−1 with a shoulder at 1510 cm−1 appearing due to NH4 disorder. The Raman spectrum of ammoniovoltaite is basically different from that of voltaite by the appearance of an intensive band centered at 3194 cm−1 and attributed to the ν3 mode of NH4. The latter can serve as a distinctive feature of ammonium in voltaite-group minerals in resemblance to recently reported results for another NH4-mineral—tschermigite, where ν3 of NH4 occurs at 3163 cm−1. The values calculated from wavenumbers of infrared bands at 3585 cm−1, 3467 cm−1 and 3400 cm−1 for hydrogen bond distances: d(O···H) and d(O···O) correspond to bonding involving H1 and H2 atoms of Fe2+X6 (X = O, OH) octahedra. The infrared bands observed at 3242 cm−1 and 2483 cm−1 are due to stronger hydrogen bonding, that may refer to non-localized H atoms of Al(H2O)6 or NH4.

Molecular Structure of Cefuroxime Axetil Complexes with α-, β-, γ-, and 2-Hydroxypropyl-β-Cyclodextrins: Molecular Simulations and Raman Spectroscopic and Imaging Studies

“…The smallest number of components is included in the band for β-CD+CA (four), and the larger in that for γ-CD+CA (eight). The 875–873 cm −1 sub-bands detected only for γ-CD+CA and 2HP-β-CD+CA may indicate additional interactions with water molecules and the external placement of hydroxyl groups [ 62 ], respectively. In the case of β-CD+CA, no bands in the 880–870 cm −1 and one band with a small contribution in 840–820 cm −1 regions were detected; the latter range is ascribed to the symmetric stretching mode of the CNC groups [ 63 ], where this share is much greater in comparison to other studied systems.…”

Preparation and characterization of an iron–β-cyclodextrin inclusion complex: factors influencing the host–guest interaction

“…The peak observed at 1645.55 cm −1 is related to the O–C–O group, while the peaks detected at 1415.53 and 1448 cm −1 are attributed to the bond vibrations of the –NH 2 group. 63,64 The corresponding peaks for the –PO and P–O–H groups can be detected at 1021 and 1077.60 cm −1 63,65 and 936 and 946 cm −1 , 63 respectively. The peaks at 435–575 cm −1 are related to the PO 4 vibrations.…”

Preclinical evaluation of Raman spectroscopy for pedicular screw insertion surgical guidance in a porcine spine model

“…Ligaments are generally composed of ground substance, collagen (mainly types I and III) with minimal elastin fibers, i.e., the building blocks are collagen fibers. Another high peak at 1641 cm−1 is assigned to water, 46 which is an important component of articular cartilage, contributing up to 80% of wet weight. Part of this water is linked to the intrafibrillar space within the collagen 47 .…”