The single-crystal Raman spectra of the natural mineral paulmooreite Pb2As2O5 from the L (a) over circle ngban, Filipstad district, Varmland province, Sweden, are presented for the first time. It is a monoclinic mineral containing an isolated [As2O5](4-) dimer. Unpolarized single-crystal spectra of the natural and synthetic samples compare favorably with each other and are characterized by strong bands around 186 and 140 cm(-1) and three medium bands at 800-700 cm(-1). Band assignments were made based on band symmetry and spectral comparison between experimental band positions and those resulting from Hartree-Fock calculation of an isolated [As2O5](4-) anion complex. Spectral comparison was also made with lead arsenites such as synthetic PbAs2O4 and Pb-2(AsO2)(3)Cl and natural finnemanite to determine the contribution of the terminal and bridging 0 in paulmooreite. Bands at 760-733 cm(-1) were assigned to terminal As-O vibrations, whereas stretches of the bridging O occur at 562 and 503 cm(-1). The single-crystal spectra showed good mode separation, allowing bands to be assigned a symmetry species of A(g) or B-g.

The single-crystal Raman spectra of minerals brandholzite and bottinoite, formula M[Sb(OH)(6)](2)center dot 6H(2)O, where M is Mg+2 and Ni+2, respectively, and the non-aligned Raman spectrum of mopungite, formula Na[Sb(OH)(6)], are presented for the first time. The mixed metal minerals comprise alternating layers of [Sb(OH)(6)](-1) octahedra and mixed [M(H2O)(6)](+2)/[Sb(OH)(6)](-1) octahedra. Mopungite comprises hydrogen-bonded layers of [Sb(OH)(6)](-1) octahedra linked within the layer by Na+ ions. The spectra of the three minerals were dominated by the Sb-O symmetric stretch of the [Sb(OH)(6)](-1) octahedron, which occurs at approximately 620 cm(-1). The Raman spectrum of mopungite showed many similarities to spectra of the di-octahedral minerals, supporting the view that the Sb octahedra give rise to most of the Raman bands observed, particularly below 1200 cm(-1). Assignments have been proposed on the basis of the spectral comparison between the minerals, prior literature and density functional theory (DFT) calculations of the vibrational spectra of the free [Sb(OH)(6)](-1) and [M(H2O)(6)](+2) octahedra by a model chemistry of B3LYP/6-31G(d) and lanl2dz for the Sb atom. The single-crystal spectra showed good mode separation, allowing most of the bands to be assigned to the symmetry species A or E. Copyright (C) 2010 John Wiley & Sons, Ltd.

The single‐crystal Raman spectra of the natural mineral finnemanite Pb5(AsO3)3Cl• from the Långban locality, Filipstad district, Värmland province, Sweden, are presented for the first time. It is a hexagonal mineral belonging to the ortho‐arsenite group, where the [AsO3]3− ion is isolated. The spectra of finnemanite are characterised by a strong band at 734 cm−1 overlying a shoulder at 726 cm−1, and broad overlapping bands in the lower wavenumber region with the strongest band positioned at 174 cm−1. Band assignments were made on the basis of band symmetry, experimental band positions from the literature, the calculated Raman spectrum using density functional theory and spectral comparison with other ortho‐arsenite minerals reinerite, cafarsite and nealite as well as with synthetic lead arsenite compounds Pb2(AsO2)3Cl, Pb2As2O5 and PbAs2O4. The band at 734 cm−1 was assigned to ν1 (AsO3); those at 726 and 640 cm−1 to ν3; those at 372 and 357 cm−1 to ν2, and those at 244, 239 and 207 cm−1 to ν4. The single‐crystal spectra of finnemanite showed good mode separation, allowing the bands to be assigned to the symmetry species Ag, E1g or E2g. Copyright © 2011 John Wiley & Sons, Ltd.

The minerals of the mixite group - zalesiite CaCu6[(AsO4)(2)(AsO3OH)(OH)(6)]center dot 3H(2)O from abandoned uranium deposit Zalesi,Czech Republic and calciopetersite CaCu6[(PO4)(2)(PO3OH)(OH)(6)]center dot 3H(2)O from a quarry near Domasov na Bystrici, northern Moravia, Czech Republic - were studied by Raman and infrared spectroscopy. The observed bands were assigned to the stretching and bending vibrations of (AsO4)(3-) and (AsO3OH)(2-) ions in zalesiite, and (PO4)(3-) and (PO3OH)(2-) in calciopetersite, and to molecular water, hydroxyl ions, and Cu-(O,OH) units in both minerals. O-H center dot center dot center dot O hydrogen-bond lengths in zalesite and calciopetersite structures were calculated with Libowitzky's empirical relation. Copyright (C) 2010 John Wiley & Sons, Ltd.

Many minerals based upon antimonite and antimonate anions remain to be studied. Most of the bands occur in the low wavenumber region, making the use of infrared spectroscopy difficult. This problem can be overcome by using Raman spectroscopy. The Raman spectra of the mineral klebelsbergite Sb4O4(OH)(2)(SO4) were studied and related to the structure of the mineral. The Raman band observed at 971 cm(-1) and a series of overlapping bands are observed at 1029, 1074, 1089, 1139 and 1142 cm(-1) are assigned to the SO42- nu(1) symmetric and nu(3) antisymmetric stretchingmodes, respectively. Two Raman bands are observed at 662 and 723 cm(-1), which are assigned to the Sb-O nu(3) antisymmetric and nu(1) symmetric stretching modes, respectively. The intense Raman bands at 581, 604 and 611 cm(-1) are assigned to the nu(4) SO42- bending modes. Two overlapping bands at 481 and 489 cm(-1) are assigned to the nu(2) SO42- bending mode. Low-intensity bands at 410, 435 and 446 cm(-1) may be attributed to O-Sb-O bending modes. The Raman band at 3435 cm(-1) is attributed to the O-H stretching vibration of the OH units. Multiple Raman bands for both SO42- and Sb-O stretching vibrations support the concept of the non-equivalence of these units in the klebelsbergite structure. It is proposed that the two sulfate anions are distorted to different extents in the klebelsbergite structure. Copyright (C) 2010 John Wiley & Sons, Ltd.

Raman spectroscopy has been used to study vanadates in the solid state. The molecular structure of the vanadate minerals vesignieite [BaCu3(VO4)(2)(OH)(2)] and volborthite [Cu3V2O7(OH)(2)center dot 2H(2)O] have been studied by Raman spectroscopy and infrared spectroscopy. The spectra are related to the structure of the two minerals. The Raman spectrum of vesignieite is characterized by two intense bands at 821 and 856 cm(-1) assigned to nu(1) (VO4)(3-) symmetric stretching modes. A series of infrared bands at 755, 787 and 899 cm(-1) are assigned to the nu(3) (VO4)(3-) antisymmetric stretching vibrational mode. Raman bands at 307 and 332 cm(-1) and at 466 and 511 cm(-1) are assigned to the nu(2) and nu(4) (VO4)(3-) bending modes. The Raman spectrum of volborthite is characterized by the strong band at 888 cm(-1), assigned to the nu(1) (VO3) symmetric stretching vibrations. Raman bands at 858 and 749 cm(-1) are assigned to the nu(3) (VO3) antisymmetric stretching vibrations; those at 814 cm(-1) to the nu(3) (VOV) antisymmetric vibrations; that at 508 cm(-1) to the nu(1) (VOV) symmetric stretching vibration and those at 442 and 476 cm(-1) and 347 and 308 cm(-1) to the nu(4) (VO3) and nu(2) (VO3) bending vibrations, respectively. The spectra of vesignieite and volborthite are similar, especially in the region of skeletal vibrations, even though their crystal structures differ. Copyright (C) 2011 John Wiley & Sons, Ltd.

ABSTRACT The mineral nealite Pb4Fe2+(AsO3)2Cl4 · 2H2O is of archaeological significance as it is man made mineral formed through the dumping of mine wastes in the sea. The mineral has been studied by Raman spectroscopy. Raman spectroscopy identifies intense Raman bands at 708 and 732 cm−1 assigned to stretching vibrations. In addition low intensity bands are observed at 604 and 632 cm−1, which are attributed to symmetric and antisymmetric stretching modes. Low intensity Raman band is observed at 831 cm−1 and is assigned to the stretching vibration. Intense Raman bands at 149 and 183 cm−1 are attributed to M-Cl stretching vibrations. Raman spectroscopy identifies arsenic anions in different oxidation states in the mineral. The molecular structure of the mineral nealite, as indicated by Raman spectroscopy, is more complex than has been reported by previous studies.

We present the first single-crystal Raman spectra of the mineral schafarzikite FeSb2O4 from the Pernek locality of the Slovak Republic. In addition, Raman spectra of the natural mineral apuanite Fe2+Fe43+Sb4O12S, originating from the Apuan Alps in Italy, as well as spectra of synthetic ZnSb2O4 and the arsenite mineral trippkeite (CuAs2O4) are presented for the first time. The spectra of the antimonite minerals are characterized by a strong band in the region 660-680 cm(-1) with shoulders on either side, and a band of medium intensity near 300 cm(-1). The spectrum of the arsenite mineral is characterized by a medium band near 780 cm(-1) with a shoulder on the high wavenumber side and a strong band at 370 cm(-1). Mode assignments are proposed based on the spectral comparison between the compounds, symmetry modes of the bands and prior literature. The single-crystal spectra of schafarzikite showed good mode separation, allowing bands to be assigned to the symmetry species of A(1g), B-1g, B-2g, or E-g.

Raman spectroscopy has enabled insights into the molecular structure of the richelsdorfite Ca2Cu5Sb[Cl vertical bar(OH)(6)vertical bar(AsO4)(4)]center dot 6H(2)O. This mineral is based upon the incorporation of arsenate or phosphate with chloride anion into the structure and as a consequence the spectra reflect the bands attributable to these anions, namely arsenate or phosphate and chloride. The richelsdorfite Raman spectrum reflects the spectrum of the arsenate anion and consists of vi at 849, nu(2) at 344 cm(-1), nu(3) at 835 and nu(4) at 546 and 498 cm(-1). A band at 268 cm(-1) is attributed to CuO stretching vibration. Low wavenumber bands at 185 and 144 cm(-1) may be assigned to CuCl TO/LO optic vibrations. (C) 2011 Elsevier B.V. All rights reserved.

Raman spectrum of burgessite, Co-2(H2O)(4)[AsO3OH] (2)center dot H2O, was studied, interpreted and compared with its infrared spectrum. The stretching and bending vibrations of (AsO3) and As-OH units, as well as the stretching, bending and libration modes of water molecules and hydroxyl ions were assigned. The range of O-H center dot center dot center dot O hydrogen bond lengths was inferred from the Raman and infrared spectra of burgessite. The presence of (AsO3OH)(2-) units in the crystal structure of burgessite was proved, which is in agreement with its recently solved crystal structure. Raman and infrared spectra of erythrite inferred from the RRUFF database are used for comparison. Copyright (C) 2010 John Wiley & Sons, Ltd.

The mineral dussertite, a hydroxy‐arsenate mineral with formula BaFe 3+ 3 (AsO 4 ) 2 (OH) 5 , has been studied by Raman spectroscopy complemented with infrared spectroscopy. The spectra of three minerals from different origins were investigated and proved to be quite similar, although some minor differences were observed. In the Raman spectra of the Czech dussertite, four bands are observed in the 800–950 cm −1 region. The bands are assigned as follows: the band at 902 cm −1 is assigned to the (AsO 4 ) 3− ν 3 antisymmetric stretching mode, the one at 870 cm −1 to the (AsO 4 ) 3− ν 1 symmetric stretching mode, and those at 859 and 825 cm −1 to the As‐O M 2 + /3+ stretching modes and/or hydroxyl bending modes. Raman bands at 372 and 409 cm −1 are attributed to the ν 2 (AsO 4 ) 3− bending mode and the two bands at 429 and 474 cm −1 are assigned to the ν 4 (AsO 4 ) 3− bending mode. An intense band at 3446 cm −1 in the infrared spectrum and a complex set of bands centred upon 3453 cm −1 in the Raman spectrum are attributed to the stretching vibrations of the hydrogen‐bonded (OH) − units and/or water units in the mineral structure. The broad infrared band at 3223 cm −1 is assigned to the vibrations of hydrogen‐bonded water molecules. Raman spectroscopy identified Raman bands attributable to (AsO 4 ) 3− and (AsO 3 OH) 2− units. Copyright © 2010 John Wiley & Sons, Ltd.

This thesis concentrates on the characterisation of selected arsenite, antimonite, and hydroxyantimonate minerals based on their vibrational spectra. A number of natural arsenite and antimonite minerals were studied by single crystal Raman spectroscopy in order to determine the contribution of bridging and terminal oxygen atoms to the vibrational spectra. A series of natural hydrated antimonate minerals was also compared and contrasted using single crystal Raman spectroscopy to determine the contribution of the isolated antimonate ion. The single crystal data allows each band in the spectrum to be assigned to a symmetry species. The contribution of bridging and terminal oxygen atoms in the case of the arsenite and antimonite minerals was determined by factor group analysis, the results of which are correlated with the observed symmetry species. In certain cases, synthetic analogues of a mineral and/or synthetic compounds isostructural or related to the mineral of interest were also prepared. These synthetic compounds are studied by non-oriented Raman spectroscopy to further aid band assignments of the minerals of interest. Other characterisation techniques include IR spectroscopy, SEM and XRD. From the single crystal data, it was found that good separation between different symmetry species is observed for the minerals studied.

The mineral nealite Pb4Fe2+(AsO3)(2)Cl-4 center dot 2H(2)O is of archaeological significance as it is man made mineral formed through the dumping of mine wastes in the sea. The mineral has been studied by Raman spectroscopy. Raman spectroscopy identifies intense Raman bands at 708 and 732 cm(-1) assigned to AsO33- stretching vibrations. In addition low intensity bands are observed at 604 and 632 cm(-1), which are attributed to As2O42- symmetric and antisymmetric stretching modes. Low intensity Raman band is observed at 831 cm(-1) and is assigned to the AsO44- stretching vibration. Intense Raman bands at 149 and 183 cm(-1) are attributed to M-Cl stretching vibrations. Raman spectroscopy identifies arsenic anions in different oxidation states in the mineral. The molecular structure of the mineral nealite, as indicated by Raman spectroscopy, is more complex than has been reported by previous studies.

Raman and infrared spectra of two polymorphous minerals with the chemical formula Fe3+(SO4)(OH)·2H2O, 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⋯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.

The mineral dussertite, a hydroxy-arsenate mineral with formula BaFe33+(AsO4)(2)(OH)(5), has been studied by Raman spectroscopy complemented with infrared spectroscopy. The spectra of three minerals from different origins were investigated and proved to be quite similar, although some minor differences were observed. In the Raman spectra of the Czech dussertite, four bands are observed in the 800-950 cm(-1) region. The bands are assigned as follows: the band at 902 cm(-1) is assigned to the (AsO4)(3-) v(3) antisymmetric stretching mode, the one at 870 cm(-1) to the (AsO4)(3-) v(1) symmetric stretching mode, and those at 859 and 825 cm(-1) to the As-OM2+/3+ stretching modes and/or hydroxyl bending modes. Raman bands at 372 and 409 cm(-1) are attributed to the V-2 (AsO4)(3-) bending mode and the two bands at 429 and 474 cm(-1) are assigned to the v(4) (AsO4)(3-) bending mode. An intense band at 3446 cm(-1) in the infrared spectrum and a complex set of bands centred upon 3453 cm(-1) in the Raman spectrum are attributed to the stretching vibrations of the hydrogen-bonded (OH)(-) units and/or water units in the mineral structure. The broad infrared band at 3223 cm(-1) is assigned to the vibrations of hydrogen-bonded water molecules. Raman spectroscopy identified Raman bands attributable to (AsO4)(3-) and (AsO3OH)(2-) units. Copyright (C) 2010 John Wiley & Sons, Ltd.

The oriented single-crystal Raman spectrum of leiteite has been obtained and the spectra related to the structure of the mineral. The intensities of the observed bands vary according to orientation, allowing them to be assigned to either A(g) or B-g modes. A(g) bands are generally the most intense in the CAAC spectrum, followed by ACCA, CBBC, and ABBA whereas B-g bands are generally the most intense in the CBAC followed by ABCA. The CAAC and ACCA spectra are identical, as are those obtained in the CBBC and ABBA orientations. Both cross-polarised spectra are identical. Band assignments were made with respect to bridging and non-bridging As-O bonds. Copyright (C) 2010 John Wiley & Sons, Ltd.

The mineral thorikosite Pb-3(OH)(SbO3,AsO3)Cl-2 is named after the ancient city of Thorikos, in the region of Attica, where the ancient mine sites dating back to the bronze ages are found. Raman spectra of the antimonite-bearing mineral thorikosite Pb-3(OH)(SbO3,AsO3)Cl-2 were studied and were related to the structure of the mineral. Two intense Raman peaks were observed at 596 and 730 cm(-1) and were assigned to the Sb3+O3 and As3+O3 stretching vibrations. A peak at 1085 cm(-1) is assigned to the Sb3+OH deformation mode. Raman band at 325 cm(-1) is assigned to an OAsO bending vibration of the As3+O3 units, and the bands at 269 and 275 cm(-1) are attributed to the OSbO bending modes of the Sb3+O3 units. The intense Raman bands at 112 and 133 cm(-1) are associated with PbCl stretching modes. Minerals such as nealite and thorikosite are minerals of archaeological significance. Yet no spectroscopic studies of these minerals had been undertaken.

Raman spectra of two well-defined types of koritnigite crystals from the Jachymov ore district, Czech Republic, were recorded and interpreted. No substantial differences were observed between both crystal types. The observed Raman bands were attributed to the (AsO3OH)(2-) stretching and bending vibrations as well as stretching and bending vibrations of water molecules and hydroxyl ions. The non-interpreted Raman spectra of koritnigite from the RRUFF database and the published infrared spectra of cobaltkoritnigite were used for comparison. The O-H center dot center dot center dot O hydrogen bond lengths in the crystal structure of koritnigite were inferred from the Raman spectra and compared with those derived from the X-ray single-crystal refinement. The presence of (AsO3OH)(2-) units in the crystal structure of koritnigite was proved from the Raman spectra, which supports the conclusions of the X-ray structure analysis. Copyright (C) 2010 John Wiley & Sons, Ltd.

Raman spectra of mineral peretaite Ca(SbO)4(OH)2(SO4)2·2H2O were studied, and related to the structure of the mineral. Raman bands observed at 978 and 980cm−1 and a series of overlapping bands observed at 1060, 1092, 1115, 1142 and 1152cm−1 are assigned to the SO42− ν1 symmetric and ν3 antisymmetric stretching modes. Raman bands at 589 and 595cm−1 are attributed to the SbO symmetric stretching vibrations. The low intensity Raman bands at 650 and 710cm−1 may be attributed to SbO antisymmetric stretching modes. Raman bands at 610cm−1 and at 417, 434 and 482cm−1 are assigned to the SO42− ν4 and ν2 bending modes, respectively. Raman bands at 337 and 373cm−1 are assigned to O–Sb–O bending modes. Multiple Raman bands for both SO42− and SbO stretching vibrations support the concept of the non-equivalence of these units in the peretaite structure.

Raman spectroscopy complemented with infrared spectroscopy was used to study the molecular structure of the mineral euchroite, a mineral involved in a complex set of equilibria between the copper hydroxy arsenates: euchroite Cu2(AsO4)(OH)·3H2O olivenite Cu2(AsO4)(OH) strashimirite Cu8(AsO4)4(OH)4·5H2O arhbarite Cu2Mg(AsO4)(OH)3. The Raman bands observed at 848 and 768 cm−1 are assigned to the ν1 and ν3 (AsO4)3− stretching vibrations. Two Raman bands at 358 and 385 cm−1 are attributed to the ν2 (AsO4)3− bending mode and two Raman bands at 441 and 474 cm−1 to the ν4 AsO43− bending modes. Two sharp Raman bands are observed at 3470 and 3537 cm−1 and are attributed to the stretching vibrations of hydroxyl units. A comparison of the Raman spectrum of euchroite is made with the other copper hydroxy arsenate minerals including strashimirite, olivenite, cornubite, and cornwallite. Copyright © 2009 John Wiley & Sons, Ltd.