Intercalation of Hydrotalcites with Hexacyanoferrate(II) and (III)-a ThermoRaman Spectroscopic Study

Raman spectroscopy using a hot stage indicates that the intercalation of hexacyanoferrate(II) and (III) in the interlayer space of a Mg,Al hydrotalcites leads to layered solids where the intercalated species is both hexacyanoferrate(II) and (III). Raman spectroscopy shows that depending on the oxidation state of the initial hexacyanoferrate partial oxidation and reduction takes place upon intercalation. For the hexacyanoferrate(III) some partial reduction occurs during synthesis. The symmetry of the hexacyanoferrate decreases from Oh existing for the free anions to D3d in the hexacyanoferrate interlayered hydrotalcite complexes. Hot stage Raman spectroscopy reveals the oxidation of the hexacyanoferrate(II) to hexacyanoferrate(III) in the hydrotalcite interlayer with the removal of the cyanide anions above 250 °C. Thermal treatment causes the loss of CN ions through the observation of a band at 2080 cm-1. The hexacyanoferrate (III) interlayered Mg,Al hydrotalcites decomposes above 150 °C

Vibrational Spectroscopy of Selected Natural Uranyl Vanadates

Raman spectroscopy has been used to study a selection of uranyl vanadate minerals including carnotite, curienite, francevillite, tyuyamunite and metatyuyamunite. The minerals are characterised by an intense band in the 800 to 824 cm-1 region, assigned to the ν1 symmetric stretching vibrations of the (UO2)2+ units. A second intense band is observed in the 965 to 985 cm-1 range and is attributed to the ν1 (VO3) symmetric stretching vibrations in the (V2O8) units. This band is split with a second component observed at around 963 cm-1. A band of very low intensity is observed around 948 cm-1 and is assigned to the ν3 antisymmetric stretching vibrations of the (VO3) units. Bands in the range 608-655 cm-1 may be attributed to molecular water librational modes or the stretching modes ￮(V2O2) units. Bands in the range 573-583 cm-1 may be connected with the ￮ (U-Oequatorial) vibrations or ￮ (V2O2) units. Bands located in the range 467-539 cm-1 may be also attributed to the ￮ (U-Oequatorial) units vibrations. The bending modes of the (VO3) units are observed in the 463 to 480 cm-1 range – there may be some coincidence with ￮ (U-Oequatorial). The bending modes of the (V2O2) in the (V2O8) units are located in a series of bands around 407, 365 and 347 cm-1 (ν2). Two intense bands are observed in the 304 to 312 cm-1 range and 241 to 264 cm-1 range and are assigned to the doubly degenerate ν2 modes of the (UO2)2+ units. The study of the vibrational spectroscopy of uranyl vanadates is complicated by the overlap of bands from the (VO3) and (UO2)2+ units. Raman spectroscopy has proven most useful in assigning bands to these two units since Raman bands are sharp and well separated as compared with infrared bands. The uranyl vanadate minerals are often found as crystals on a host matrix and Raman spectroscopy enables their in-situ characterisation without sample preparation

Molecular structure of the phosphate mineral koninckite - a vibrational spectroscopic study

We have undertaken a study of the mineral koninckite from Litosice (Czech Republic), a hydrated ferric phosphate, using a combination of scanning electron microscopy with electron probe micro-analyzer (wavelength-dispersive spectroscopy) and vibrational spectroscopy. Chemical analysis shows that studied koninckite is a pure phase with an empirical formula Fe3+ (0.99)(PO4)(1.00) center dot 2.75 H2O, with minor enrichment in Al, Ca, Ti, Si, Zn, and K (averages 0.00X apfu). Raman bands and shoulders at 3495, 3312, 3120, and 2966 cm(-1) and infrared bands and shoulders at 3729, 3493, 3356, 3250, 3088, 2907, and 2706 cm(-1) are assigned to the nu OH stretching of structurally distinct differently hydrogen bonded water molecules, A Raman band at 1602 cm(-1) and shoulders at 1679, 1659, 1634, and 1617 cm(-1) and infrared bands at 1650 and 1598 cm(-1) are assigned to the nu(2)(delta) H2O bending vibrations of structurally distinct differently hydrogen bonded water molecules. Raman shoulders at 1576, 1554, 1541, 1532, and 1520 cm(-1) and infrared shoulders at 1541 and 1454 cm(-1) may be probably connected with zeolitically bonded water molecules located in the channels. Raman bands and shoulders at 1148, 1132, 1108, 1063, 1048, and 1015 cm(-1) and an infrared band and shoulders at 1131, 1097, 1049, and 1017 cm(-1) are assigned to the nu(3) PO43- triply degenerate antisymmetric stretching vibrations. A Raman band and a shoulder at 994 and 970 cm(-1), respectively, and an infrared band and a shoulder at 978 and 949 cm(-1), respectively, are assigned to the nu(1) PO43- symmetric stretching vibrations. Infrared shoulders at 873, 833, and 748 cm(-1) are assigned to libration modes of water molecules. Raman bands and shoulders at 670, 648, 631, 614, 600, 572, and 546 cm(-1) and infrared bands at 592 and 534 cm(-1) are assigned to the nu(4) (delta) PO(4)(3-)triply degenerate out-of-plane bending vibrations; weak band at 570 cm(-1) may coincide with the delta Fe-O bending vibration. Raman bands and shoulders at 453, 443, 419, and 400 cm(-1) are assigned to the nu(2) (delta) PO43- doubly degenerate in-plane bending vibrations. Raman bands at 385, 346, 324, 309, 275, 252, and 227 cm(-1) are assigned to the nu Fe-O stretching vibrations in FeO6 octahedra. Raman bands at 188, 158, 140, 112, 89, and 73 cm(-1) are assigned to lattice vibrations

Dussertite BaFe3+3(AsO4)2(OH)5 : a Raman spectroscopic study of a hydroxy-arsenate mineral

The mineral dussertite, a hydroxy-arsenate mineral of formula BaFe3+3(AsO4)2(OH)5, has been studied by Raman complimented with infrared spectroscopy. The spectra of three minerals from different origins were investigated and proved quite similar, although some minor differences were observed. In the Raman spectra of Czech dussertite, four bands are observed in the 800 to 950 cm-1 region. The bands are assigned as follows: the band at 902 cm-1 is assigned to the (AsO4)3- ν3 antisymmetric stretching mode, at 870 cm-1 to the (AsO4)3- ν1 symmetric stretching mode, and both at 859 cm-1 and 825 cm-1 to the As-OM2+/3+ stretching modes/and or hydroxyls bending modes. Raman bands at 372 and 409 cm-1 are attributed to the ν2 (AsO4)3- bending mode and the two bands at 429 and 474 cm-1 are assigned to the ν4 (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

Spectrochimica Acta Part A 62 (2005) 176-180 Raman spectroscopy of halotrichite from Jaroso, Spain

Abstract Raman spectroscopy complimented with infrared ATR spectroscopy has been used to characterise a halotrichite FeSO 4 ·Al 2 (SO 4 ) 3 ·22H 2 O from The Jaroso Ravine, Almeria, Spain. Halotrichites form a continuous solid solution series with pickingerite and chemical analysis shows that the jarosite contains 6% Mg 2+ . Halotrichite is characterised by four infrared bands at 3569.5, 3485.7, 3371.4 and 3239.0 cm −1 . Using Libowitsky type relationships, hydrogen bond distances of 3.08, 2.876, 2.780 and 2.718Å were determined. Two intense Raman bands are observed at 987.7 and 984.4 cm −1 and are assigned to the ν 1 symmetric stretching vibrations of the sulphate bonded to the Fe 2+ and the water units in the structure. Three sulphate bands are observed at 77 K at 1000.0, 991.3 and 985.0 cm −1 suggesting further differentiation of the sulphate units. Raman spectrum of the ν 2 and ν 4 region of halotrichite at 298 K shows two bands at 445.1 and 466.9 cm −1 , and 624.2 and 605.5 cm −1 , respectively, confirming the reduction of symmetry of the sulphate in halotrichite

A vibrational spectroscopic study of the copper bearing silicate mineral luddenite.

The molecular structure of the copper?lead silicate mineral luddenite has been analysed using vibrational spectroscopy. The mineral is only one of many silicate minerals containing copper. The intense Raman band at 978 cm 1 is assigned to the m1 (A1g) symmetric stretching vibration of Si5O14 units. Raman bands at 1122, 1148 and 1160 cm 1 are attributed to the m3 SiO4 antisymmetric stretching vibrations. The bands in the 678?799 cm 1 are assigned to OSiO bending modes of the (SiO3)n chains. Raman bands at 3317 and 3329 cm 1 are attributed to water stretching bands. Bands at 3595 and 3629 cm 1 are associated with the stretching vibrations of hydroxyl units suggesting that hydroxyl units exist in the structure of luddenite

Konstruksi gender dalam Novel Isinga karya Dorothea Rosa Herliany

Molecular structures of the basic copper arsenate minerals olivenite, cornubite, cornwallite, and clinoclase were studied using a combination of infrared emission spectroscopy and Raman spectroscopy. Infrared emission spectra of the basic copper arsenates were obtained over the temperature range 100 to 1000°C. The IR emission spectra of the four minerals are different, in line with differences in crystal structure and composition. The Raman spectra are similar, particularly in the OH-stretching region, but characteristic differences in the deformation regions are observed. Differences are also observed in the arsenate stretching and bending regions. Infrared emission studies show that the minerals are completely dehydroxylated by 550°C