16 research outputs found
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
Raman Spectroscopy of Lead Sulphate-Carbonate Minerals-Implications for Hydrogen Bonding
The Raman spectrum of the basic carbonate-sulphate minerals known as leadhillite, susannite and caledonite have been measured and the spectra compared with the Raman spectra of cerussite, hydrocerussite and anglesite. Characteristic spectral patterns are observed for each mineral. The wavenumber position of the hydroxyl stretching bands is used to estimate the hydrogen bond distances in the minerals. The hydrogen bond distances for leadhillite polymorphs vary from 2.783 to 2.916 Å. In comparison the estimated hydrogen bond distances for hydrocerussite are much longer with values of 2.961 and 3.127 Å. The width of the hydroxyl stretching vibration provides an estimate of the variation of hydrogen bond distances for the OH groups in the mineral. The variation in bond length is greater for the longer hydrogen bonds. Characteristic sulphate and carbonate vibrations are also identified
Vibrational spectroscopy of the basic manganese, ferric and ferrous phosphate minerals: strunzite, ferristrunzite and ferrostrunzite
The Raman spectra of strunzite, ferristrunzite and ferrostrunzite have been obtained at 298 and 77K using a combination of a thermal stage and Raman microscopy. These spectra are compared with their infrared spectra. The vibrational spectra of the two minerals are different, in line with differences in crystal structure and composition. Some similarity in the Raman spectra of the hydroxyl-stretching region exists, particularly at 298K, but characteristic differences in the OH deformation regions are observed. Significant shifts in the position of the Raman bands are observed by obtaining the spectra at 77K. Differences are also observed in the phosphate stretching and deformation regions
X-ray photoelectron spectroscopy and Raman microscopy of a ferroan platinum crystal from the Kondyor Massif, Russian Far East
Raman spectroscopy of the copper chloride minerals nantokite, eriochalcite and claringbullite - implications for copper corrosion
The application of Raman spectroscopy to the study of the copper chloride minerals nantokite, eriochalcite and claringbullite has enabled the vibrational modes for the CuCl, CuOH and CuOH2 to be determined. Nantokite is characterised by bands at 205 and 155 cm-1 attributed to the transverse and longitudinal optic vibrations. Nantokite also has an intense band at 463 cm-1, eriochalcite at 405 and 390 cm-1 and claringbullite at 511 cm-1. These bands are attributed to CuO stretching modes. Water librational bands at around 672 cm-1 for eriochalcite have been identified and hydroxyl deformation modes of claringbullite at 970, 906 and 815 cm-1 are observed. Spectra of the three minerals are so characteristically different that the minerals are readily identified by Raman spectroscopy. The minerals are often determined in copper corrosion products by X-ray diffraction. Raman spectroscopy offers a rapid, in-situ technique for the identification of these corrosion products
Raman spectroscopy of the copper chloride minerals nantokite, eriochalcite and claringbullite : implications for copper corrosion
The application of Raman spectroscopy to the study of the copper chloride minerals nantokite, eriochalcite and claringbullite has enabled the vibrational modes for the CuCl, CuOH and CuOH₂ to be determined. Nantokite is characterised by bands at 205 and 155 cm⁻¹ attributed to the transverse and longitudinal optic vibrations. Nantokite also has an intense band at 463 cm⁻¹, eriochalcite at 405 and 390 cm⁻¹ and claringbullite at 511 cm⁻¹. These bands are attributed to CuO stretching modes. Water librational bands at around 672 cm⁻¹ for eriochalcite have been identified and hydroxyl deformation modes of claringbullite at 970, 906 and 815 cm⁻¹ are observed. Spectra of the three minerals are so characteristically different that the minerals are readily identified by Raman spectroscopy. The minerals are often determined in copper corrosion products by X-ray diffraction. Raman spectroscopy offers a rapid, in-situ technique for the identification of these corrosion products
Raman and Infrared Spectroscopic Study of the Vivianite-group Phosphates Vivianite, Baricite and Bobierrite
The molecular structure of the three vivianite-structure, compositionally related phosphate minerals vivianite, baricite and bobierrite of formula M32+(PO4)2.8H2O where M is Fe or Mg, has been assessed using a combination of Raman and infrared (IR) spectroscopy. The Raman spectra of the hydroxyl-stretching region are complex with overlapping broad bands. Hydroxyl stretching vibrations are identified at 3460, 3281, 3104 and 3012 cm–1 for vivianite. The high wavenumber band is attributed to the presence of FeOH groups. This complexity is reflected in the water HOH-bending modes where a strong IR band centred around 1660 cm–1 is found. Such a band reflects the strong hydrogen bonding of the water molecules to the phosphate anions in adjacent layers. Spectra show three distinct OH-bending bands from strongly hydrogen-bonded, weakly hydrogen bonded water and non-hydrogen bonded water. The Raman phosphate PO-stretching region shows strong similarity between the three minerals. In the IR spectra, complexity exists with multiple antisymmetric stretching vibrations observed, due to the reduced tetrahedral symmetry. This loss of degeneracy is also reflected in the bending modes. Strong IR bands around 800 cm–1 are attributed to water librational modes. The spectra of the three minerals display similarities due to their compositions and crystal structures, but sufficient subtle differences exist for the spectra to be useful in distinguishing the species
Raman spectroscopy of basic copper(II) and some complex copper(II) sulfate minerals : implications for hydrogen bonding
Raman spectroscopy has been applied to the study of basic Cu sulfates including antlerite, brochiantite, posnjakite, langite, and wroewolfeite and selected complex Cu sulfate minerals. Published X-ray diffraction data were used to estimate possible hydrogen bond distances for the basic Cu sulfate minerals. A Libowitzky empirical expression was used to predict hydroxyl-stretching frequencies and agreement with the observed values was excellent. This type of study was then extended to complex basic Cu sulfates: cyanotrichite, devilline, glaucocerinite, serpierite, and ktenasite. The position of the hydroxyl-stretching vibration was used to estimate the hydrogen bond distances between the OH and the SO₄ units. The variation in bandwidth of the OH-stretching bands provided an estimate of the variation in these hydrogen bond distances. By plotting the hydrogen bond O...O distance as a function of the position of the SO₄ symmetric stretching vibration, the position of the SO₄ symmetric stretching band was found to be dependent upon the hydrogen bond distance for both the basic Cu sulfates and the complex Cu sulfates