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1.
The mineral xocomecatlite is a hydroxy metatellurate mineral with Te6+ O4 units. Tellurates may be subdivided according to their formula into three types of tellurate minerals: type (a) (AB)m (TeO4)pZq, type (b) (AB)m(TeO6)·xH2O and (c) compound tellurates in which a second anion including the tellurite anion, is involved. The mineral xocomecatlite is an example of the first type. Raman bands for xocomecatlite at 710, 763 and 796 cm−1, and 600 and 680 cm−1 are attributed to the ν1(TeO4)2− symmetric and ν3 antisymmetric stretching mode. Raman bands observed at 2867 and 2926 cm−1 are assigned to TeOH stretching vibrations and enable estimation of the hydrogen bond distances of 2.622 Å (2867 cm−1), 2.634 Å (2926 cm−1) involving these OH units. The hydrogen bond distances are very short implying that they are necessary for the stability of the mineral. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
2.
Selenites and tellurites may be subdivided according to formula and structure. There are five groups, based upon the formulae (a) A(XO3), (b) A(XO3·) xH2O, (c) A2(XO3)3·xH2O, (d) A2(X2O5) and (e) A(X3O8). Of the selenites, molybdomenite is an example of type (a); chalcomenite, clinochalcomenite, cobaltomenite and ahlfeldite are minerals of type (b); mandarinoite Fe2Se3O9·6H2O is an example of type (c). Raman spectroscopy has been used to characterise the mineral mandarinoite. The intense, sharp band at 814 cm−1 is assigned to the symmetric stretching (Se3O9)6− units. Three Raman bands observed at 695, 723 and 744 cm−1 are attributed to the ν3 (Se3O9)6− anti‐symmetric stretching modes. Raman bands at 355, 398 and 474 cm−1 are assigned to the ν4 and ν2 bending modes. Raman bands are observed at 2796, 2926, 3046, 3189 and 3507 cm−1 and are assigned to OH stretching vibrations. The observation of multiple OH stretching vibrations suggests the non‐equivalence of water in the mandarinoite structure. The use of the Libowitzky empirical function provides hydrogen bond distances of 2.633(9) Å (2926 cm−1), 2.660(0) Å (3046 cm−1), 2.700(0) Å (3189 cm−1) and 2.905(3) Å (3507 cm−1). The sharp, intense band at 3507 cm−1 may be due to hydroxyl units. It is probable that some of the selenite units have been replaced by hydroxyl units. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
3.
Tellurites may be subdivided according to formula and structure. There are five groups based upon the formulae (a) A(XO3), (b) A(XO3)·xH2O, (c) A2(XO3)3·xH2O, (d) A2(X2O5) and (e) A(X3O8). Raman spectroscopy has been used to study the tellurite minerals teineite and graemite; both contain water as an essential element of their stability. The tellurite ion should show a maximum of six bands. The free tellurite ion will have C3v symmetry and four modes, 2A1 and 2 E. Raman bands for teineite at 739 and 778 cm−1 and for graemite at 768 and 793 cm−1 are assigned to the ν1 (TeO3)2− symmetric stretching mode while bands at 667 and 701 cm−1 for teineite and 676 and 708 cm−1 for graemite are attributed to the ν3 (TeO3)2− antisymmetric stretching mode. The intense Raman band at 509 cm−1 for both teineite and graemite is assigned to the water librational mode. Raman bands for teineite at 318 and 347 cm−1 are assigned to the (TeO3)2−ν2(A1) bending mode and the two bands for teineite at 384 and 458 cm−1 may be assigned to the (TeO3)2−ν4(E) bending mode. Prominent Raman bands, observed at 2286, 2854, 3040 and 3495 cm−1, are attributed to OH stretching vibrations. The values for these OH stretching vibrations provide hydrogen bond distances of 2.550(6) Å (2341 cm−1), 2.610(3) Å (2796 cm−1) and 2.623(2) Å (2870 cm−1) which are comparatively short for secondary minerals. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
4.
The mixed anion mineral dixenite has been studied by Raman spectroscopy, complemented with infrared spectroscopy. The Raman spectrum of dixenite shows bands at 839 and 813 cm−1 assigned to the (AsO3)3− symmetric and antisymmetric stretching modes. The most intense Raman band of dixenite is the band at 526 cm−1 and is assigned to the ν2 AsO33− bending mode. DFT calculations enabled the calculation of the position of AsO22− symmetric stretching mode at 839 cm−1, the antisymmetric stretching mode at 813 cm−1, and the deformation mode at 449 cm−1. The Raman bands at 1026 and 1057 cm−1 are assigned to the SiO42− symmetric stretching vibrations and those at 1349 and 1386 cm−1 to the SiO42− antisymmetric stretching vibrations. Both Raman and infrared spectra indicate the presence of water in the structure of dixenite. This brings into question the commonly accepted formula of dixenite as CuMn2+14Fe3+(AsO3)5(SiO4)2(AsO4)(OH)6. The formula may be better written as CuMn2+14Fe3+(AsO3)5(SiO4)2(AsO4)(OH)6·xH2O. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
5.
Ray L. Frost 《Journal of Raman spectroscopy : JRS》2011,42(5):1130-1134
Raman spectroscopy has been used to study selected mineral samples of the copiapite group. Copiapite (Fe2+Fe3+(SO4)6(OH)2 · 20H2O) is a secondary mineral formed through the oxidation of pyrite. Minerals of the copiapite group have the general formula AFe4(SO4)6(OH)2 · 20H2O, where A has a + 2 charge and can be either magnesium, iron, copper, calcium and/or zinc. The formula can also be B2/3Fe4(SO4)6(OH)2 · 20H2O, where B has a + 3 charge and may be either aluminium or iron. For each mineral, two Raman bands are observed at around 992 and 1029 cm−1, assigned to the (SO4)2−ν1 symmetric stretching mode. The observation of two bands provides evidence for the existence of two non‐equivalent sulfate anions in the mineral structure. Three Raman bands at 1112, 1142 and 1161 cm−1 are observed in the Raman spectrum of copiapites, indicating a reduction of symmetry of the sulfate anion in the copiapite structure. This reduction in symmetry is supported by multiple bands in the ν2 and ν4(SO4)2− spectral regions. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
6.
Ray L. Frost Sara J. Palmer Dermot A. Henry Ross Pogson 《Journal of Raman spectroscopy : JRS》2011,42(6):1447-1454
The mineral ardealite Ca2(HPO4)(SO4)·4H2O is a ‘cave’ mineral and is formed through the reaction of calcite with bat guano. The mineral shows disorder and the composition varies depending on the origin of the mineral. Raman spectroscopy complimented with infrared spectroscopy has been used to characterise the mineral ardealite. The Raman spectrum is very different from that of gypsum. Bands are assigned to SO42− and HPO42− stretching and bending modes. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
7.
Jií ejka Jií Sejkora Ray L. Frost Eloise C. Keeffe 《Journal of Raman spectroscopy : JRS》2009,40(11):1521-1526
Raman spectra of natrouranospinite complemented with infrared spectra were studied and related to the structure of the mineral. Observed bands were assigned to the stretching and bending vibrations of (UO2)2+ and (AsO4)3− units and of water molecules. U O bond lengths in uranyl and O H···O hydrogen bond lengths were calculated from the Raman and infrared spectra. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
8.
Ray L. Frost Jií Sejkora Jií ejka Eloise C. Keeffe 《Journal of Raman spectroscopy : JRS》2009,40(11):1546-1550
The mixed anion mineral parnauite Cu9[(OH)10|SO4|(AsO4)2]·7H2O has been studied by Raman spectroscopy. Characteristic bands associated with arsenate, sulphate and hydroxyl units are identified. Broad bands are observed and are resolved into component bands. Two intense bands at 859 and 830 cm−1 are assigned to the ν1 (AsO4)3− symmetric stretching and ν3 (AsO4)3− antisymmetric stretching modes. The comparatively sharp band at 976 cm−1 is assigned to the ν1 (SO4)2− symmetric stretching mode and a broad‐spectral profile centered upon 1097 cm−1 is attributed to the ν3 (SO4)2− antisymmetric stretching mode. A comparison of the Raman spectra is made with other arsenate‐bearing minerals such as carminite, clinotyrolite, kankite, tilasite and pharmacosiderite. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
9.
Ray L. Frost Marilla J. Dickfos Eloise C. Keeffe 《Journal of Raman spectroscopy : JRS》2008,39(12):1784-1788
Raman spectroscopy has been used to study zemannite Mg0.5[Zn2+Fe3+(TeO3)3]4.5H2O and emmonsite Fe23+Te34+O9·2H2O. Raman bands for zemannite and emmonsite, observed at 740 and 650 cm−1 and at 764 and 788 cm−1, respectively, are attributed to the ν1 (TeO3)2− symmetric stretching mode. The splitting of the symmetric stretching mode for emmonsite is in harmony with the results of X‐ray crystallography which shows three non‐equivalent TeO3 units in the crystal structure. Two bands at 658 and 688 cm−1 are assigned to ν3 (TeO3)2− anti‐symmetric stretching modes. Raman bands observed at 372 and 408 cm−1 for zemannite and 397 and 414 cm−1 for emmonsite are attributed to the (TeO3)2−ν2(A1) bending mode. The two Raman bands at 400 and 440 cm−1 for emmonsite are ascribed to the ν4(E) bending modes, while the band at 326 cm−1 is due to the ν2(A1) bending vibration. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
10.
11.
Ray L. Frost Jií ejka Jií Sejkora Daniel Ozdín Silmarilly Bahfenne Eloise C. Keeffe 《Journal of Raman spectroscopy : JRS》2009,40(12):1907-1910
Raman spectra of brandholzite Mg[Sb2(OH)12]·6H2O were studied, complemented with infrared spectra, and related to the structure of the mineral. An intense Raman sharp band at 618 cm−1 is attributed to the SbO symmetric stretching mode. The low‐intensity band at 730 cm−1 is ascribed to the SbO antisymmetric stretching vibration. Low‐intensity Raman bands were found at 503, 526 and 578 cm−1. Corresponding infrared bands were observed at 527, 600, 637, 693, 741 and 788 cm−1. Four Raman bands observed at 1043, 1092, 1160 and 1189 cm−1 and eight infrared bands at 963, 1027, 1055, 1075, 1108, 1128, 1156 and 1196 cm−1 are assigned to δ SbOH deformation modes. A complex pattern resulting from the overlapping band of the water and hydroxyl units is observed. Raman bands are observed at 3240, 3383, 3466, 3483 and 3552 cm−1; infrared bands at 3248, 3434 and 3565 cm−1. The Raman bands at 3240 and 3383 cm−1 and the infrared band at 3248 cm−1 are assigned to water‐stretching vibrations. The two higher wavenumber Raman bands observed at 3466 and 3552 cm−1 and two infrared bands at 3434 and 3565 cm−1 are assigned to the stretching vibrations of the hydroxyl units. Observed Raman and infrared bands in the OH stretching region are associated with O‐H···O hydrogen bonds and their lengths 2.72, 2.79, 2.86, 2.88 and 3.0 Å (Raman) and 2.73, 2.83 and 3.07 Å (infrared). Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
12.
Jií ejka Jií Sejkora Ray L. Frost Eloise C. Keeffe 《Journal of Raman spectroscopy : JRS》2009,40(12):1786-1790
Raman spectra of metauranospinite Ca[(UO2)(AsO4)]2·8H2O complemented with infrared spectra were studied. Observed bands were assigned to the stretching and bending vibrations of (UO2)2+ and (AsO4)3− units and of water molecules. U O bond lengths in uranyl and O H···O hydrogen bond lengths were calculated from the Raman and infrared spectra. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
13.
Raman spectroscopy was used to study the mineral bottinoite and a comparison with the Raman spectra of brandholzite was made. An intense sharp Raman band at 618 cm−1 is attributed to the SbO symmetric stretching mode. The low intensity band at 735 cm−1 is ascribed to the SbO antisymmetric stretching vibration. Low intensity Raman bands were found at 501, 516 and 578 cm−1. Four Raman bands observed at 1045, 1080, 1111 and 1163 cm−1 are assigned to δ SbOH deformation modes. A complex pattern resulting from the overlapping band of the water and hydroxyl units is observed. Raman bands are observed at 3223, 3228, 3368, 3291, 3458 and 3510 cm−1. The first two Raman bands are assigned to water stretching vibrations. The two higher wavenumber Raman bands observed at 3466 and 3552 cm−1 and two infrared bands at 3434 and 3565 cm−1 are assigned to the stretching vibrations of the hydroxyl units. Observed Raman and infrared bands are connected with O H···O hydrogen bonds and their lengths 2.72, 2.79, 2.86, 2.88 and 3.0 Å (Raman) and 2.73, 2.83 and 3.07 Å (infrared). Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
14.
The two minerals diadochite and destinezite of formula Fe2(PO4,SO4)2(OH)· 6H2O have been characterised by Raman spectroscopy and complemented with infrared spectroscopy. Both these minerals are found in soils and are identical except for their morphology. Diadochite is amorphous whereas destinezite is highly crystalline. The spectra of diadochite are broad and ill defined, whereas the spectra of destinezite are intense and well defined. Bands are assigned to phosphate and sulfate stretching and bending modes. Two symmetric stretching modes for both phosphate and sulfate support the concept of non‐equivalent phosphate and sulfate units in the mineral structure. Multiple water bending and stretching modes imply that non‐equivalent water molecules in the structure exist with different hydrogen‐bond strengths. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
15.
Raman spectroscopic study of the magnesium carbonate mineral hydromagnesite (Mg5[(CO3)4(OH)2]· 4H2O)
Ray L. Frost 《Journal of Raman spectroscopy : JRS》2011,42(8):1690-1694
Magnesium minerals are important for understanding the concept of geosequestration. One method of studying the hydrated hydroxy magnesium carbonate minerals is through vibrational spectroscopy. A combination of Raman and infrared spectroscopy has been used to study the mineral hydromagnesite. An intense band is observed at 1121 cm−1, attributed to the CO32−ν1 symmetric stretching mode. A series of infrared bands at 1387, 1413 and 1474 cm−1 are assigned to the CO32−ν3 antisymmetric stretching modes. The CO32−ν3 antisymmetric stretching vibrations are extremely weak in the Raman spectrum and are observed at 1404, 1451, 1490 and 1520 cm−1. A series of Raman bands at 708, 716, 728 and 758 cm−1 are assigned to the CO32−ν2 in‐plane bending mode. The Raman spectrum in the OH stretching region is characterized by bands at 3416, 3516 and 3447 cm−1. In the infrared spectrum, a broad band is found at 2940 cm−1, which is assigned to water stretching vibrations. Infrared bands at 3430, 3446, 3511, 2648 and 3685 cm−1 are attributed to MgOH stretching modes. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
16.
Jan Loun Jií ejka Jií Sejkora Jakub Plil Milan Novk Ray L. Frost Sara J. Palmer Eloise C. Keeffe 《Journal of Raman spectroscopy : JRS》2011,42(7):1596-1600
The Raman spectrum of bukovskýite [Fe3+2(OH)(SO4)(AsO4)· 7H2O] has been studied and compared with that of an amorphous gel containing specifically Fe, As and S, which is understood to be an intermediate product in the formation of bukovskýite. The observed bands are assigned to the stretching and bending vibrations of (SO4)2− and (AsO4)3− units, stretching and bending vibrations and vibrational modes of hydrogen‐bonded water molecules, stretching and bending vibrations of hydrogen‐bonded (OH)− ions and Fe3+ (O,OH) units. The approximate range of O H···O hydrogen bond lengths was inferred from the Raman spectra. Raman spectra of crystalline bukovskýite and of the amorphous gel differ in that the bukovskýite spectrum is more complex, the observed bands are sharp and the degenerate bands of (SO4)2− and (AsO4)3− are split and more intense. Lower wavenumbers of δ H2O bending vibrations in the spectrum of the amorphous gel may indicate the presence of weaker hydrogen bonds compared to those in bukovskýite. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
17.
Raman spectroscopy has been used to study the selenite mineral ahlfeldite. A comparison is made with the Raman spectra of chalcomenite, cobaltomenite and clinochalcomenite. Selenite minerals are characterised by the position of the symmetric stretching mode which is observed at higher wavenumbers than the anti‐symmetric stretching mode. The selenite ion has C3v symmetry and four modes, 2A1 and 2E. These modes are observed at 813, 472 cm−1 (A1) and 685, 710, 727 and 367 and 396 cm−1 (E). Bands assigned to the water stretching vibrations are observed for ahlfeldite at 3385 cm−1, for chalcomenite at 2953, 3184 and 3506 cm−1 and for clinochalcomenite at 2909, 3193 and 3507 cm−1. A comparison of the Raman spectra of chalcomenite, clinochalcomenite and cobaltomenite is made. The position of these bands enabled hydrogen bond distances in the selenite structure to be estimated. Hydrogen bond distances for ahlfeldite, chalcomenite and clinochalcomenite were determined to be similar. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
18.
Ray L. Frost Jií Sejkora Eloise C. Keeffe Jakub Plil Jií ejka Silmarilly Bahfenne 《Journal of Raman spectroscopy : JRS》2010,41(2):202-206
Raman spectroscopy has been used to study the rare‐earth mineral churchite‐(Y) of formula (Y,REE)(PO4) ·2H2O, where rare‐earth element (REE) is a rare‐earth element. The mineral contains yttrium and, depending on the locality, a range of rare‐earth metals. The Raman spectra of two churchite‐(Y) mineral samples from Jáchymov and Medvědín in the Czech Republic were compared with the Raman spectra of churchite‐(Y) downloaded from the RRUFF data base. The Raman spectra of churchite‐(Y) are characterized by an intense sharp band at 975 cm−1 assigned to the ν1 (PO43−) symmetric stretching mode. A lower intensity band observed at around 1065 cm−1 is attributed to the ν3 (PO43−) antisymmetric stretching mode. The (PO43−) bending modes are observed at 497 cm−1 (ν2) and 563 cm−1 (ν4). Some small differences in the band positions between the four churchite‐(Y) samples from four different localities were found. These differences may be ascribed to the different compositions of the churchite‐(Y) minerals. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
19.
Raman spectra of dumontite were measured at 298 and 77 K. Observed bands were attributed to the stretching and bending vibrations of uranyl and phosphate units and OH stretching vibrations of water molecules. U–O bond lengths in uranyls and approximate O–H···O bond lengths were calculated. The values of the U–O bond lengths are in agreement with the data from the single crystal structure analysis of dumontite. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
20.
Ray L. Frost Sara J. Palmer Frederick Theiss 《Journal of Raman spectroscopy : JRS》2011,42(5):1163-1167
We have successfully synthesised hydrotalcites (HTs) containing calcium, which are naturally occurring minerals. Insight into the unique structure of HTs has been obtained using a combination of X‐ray diffraction (XRD) as well as infrared and Raman spectroscopies. Calcium‐containing hydrotalcites (Ca‐HTs) of the formula Ca4Al2(CO3)(OH)12·4H2O (2:1 Ca‐HT) to Ca8Al2(CO3)(OH)20· 4H2O (4:1 Ca‐HT) have been successfully synthesised and characterised by XRD and Raman spectroscopy. XRD has shown that 3:1 calcium HTs have the largest interlayer distance. Raman spectroscopy complemented with selected infrared data has been used to characterise the synthesised Ca‐HTs. The Raman bands observed at around 1086 and 1077 cm−1 were attributed to the ν1 symmetric stretching modes of the (CO32−) units of calcite and carbonate intercalated into the HT interlayer. The corresponding ν3 CO32− antisymmetric stretching modes are found at around 1410 and 1475 cm−1. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献