In this paper, we provide a crystal-chemical investigation of metavauxite, ideally FeAl2(PO4)2(OH)2·8H2O, from Llallagua (Bolivia) by using a multi-methodological approach based on EDS microchemical analysis, single crystal X-ray diffraction, and Raman and Fourier transform infrared (FTIR) spectroscopy. Our new diffraction results allowed us to locate all hydrogen atoms from the structure refinements in the monoclinic P21/cspace group. Metavauxite structure displays a complex framework consisting of a stacking of [Al(PO4)3(OH)(H2O)2]7−layers linked to isolated [Fe(H2O)6]2+cationic octahedral complex solely by hydrogen bonding. The hydrogen-bonding scheme was inferred from bond-valence calculations and donor-acceptor distances. Accordingly, strong hydrogen bonds, due to four coordinated H2O molecules, bridge the [Fe(H2O)6]2+units to the Al/P octahedral/tetrahedral layer. The hydroxyl group, coordinated by two Al atoms, contributes to the intra-layer linkage. FTIR and Raman spectra in the high-frequency region (3700–3200 cm−1) are very similar, and show a complex broad band consisting of several overlapping components due to the H2O molecules connecting the isolated Fe(H2O)6and the adjacent Al/P octahedral/tetrahedral layers. A sharp peak at 3540 cm−1 is assigned to the stretching mode of the OH group. The patterns collected in the low-frequency region are dominated by the stretching and bending modes of the PO4 3−group and the metal-oxygen polyhedra

Della Ventura, G., Capitelli, F., Capitani, G., Ventruti, G., Monno, A. (2019). X-ray Structure Refinement and Vibrational Spectroscopy of Metavauxite FeAl2(PO4)2(OH)2·8H2O. CRYSTALS, 9(6) [10.3390/cryst9060297].

X-ray Structure Refinement and Vibrational Spectroscopy of Metavauxite FeAl2(PO4)2(OH)2·8H2O

Capitani, G
Membro del Collaboration Group
;
2019

Abstract

In this paper, we provide a crystal-chemical investigation of metavauxite, ideally FeAl2(PO4)2(OH)2·8H2O, from Llallagua (Bolivia) by using a multi-methodological approach based on EDS microchemical analysis, single crystal X-ray diffraction, and Raman and Fourier transform infrared (FTIR) spectroscopy. Our new diffraction results allowed us to locate all hydrogen atoms from the structure refinements in the monoclinic P21/cspace group. Metavauxite structure displays a complex framework consisting of a stacking of [Al(PO4)3(OH)(H2O)2]7−layers linked to isolated [Fe(H2O)6]2+cationic octahedral complex solely by hydrogen bonding. The hydrogen-bonding scheme was inferred from bond-valence calculations and donor-acceptor distances. Accordingly, strong hydrogen bonds, due to four coordinated H2O molecules, bridge the [Fe(H2O)6]2+units to the Al/P octahedral/tetrahedral layer. The hydroxyl group, coordinated by two Al atoms, contributes to the intra-layer linkage. FTIR and Raman spectra in the high-frequency region (3700–3200 cm−1) are very similar, and show a complex broad band consisting of several overlapping components due to the H2O molecules connecting the isolated Fe(H2O)6and the adjacent Al/P octahedral/tetrahedral layers. A sharp peak at 3540 cm−1 is assigned to the stretching mode of the OH group. The patterns collected in the low-frequency region are dominated by the stretching and bending modes of the PO4 3−group and the metal-oxygen polyhedra
Articolo in rivista - Articolo scientifico
metavauxite; phosphate; single-crystal X-ray structure refinement; hydrogen bonding network; FTIR and Raman spectroscopy
English
2019
9
6
297
open
Della Ventura, G., Capitelli, F., Capitani, G., Ventruti, G., Monno, A. (2019). X-ray Structure Refinement and Vibrational Spectroscopy of Metavauxite FeAl2(PO4)2(OH)2·8H2O. CRYSTALS, 9(6) [10.3390/cryst9060297].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/262370
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