Studies on antimony oxides: Part I (original) (raw)
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Thermal decomposition of antimony oxyhalides
Journal of Thermal Analysis, 1990
The thermal decomposition of SbOCl, Sb405C12 and Sb8OllC12 has been studied by thermogravimetry with identification of the products resulting in the condensed phase by X-ray diffraction and infrared technique. It is shown that in nitrogen SbOCI undergoes progressive stepwise thermal disproportionation to Sb203 and SbCI3 with formation of Sb405C12 and Sb8OllC12 and as intermediates. It is thus confirmed that Sb304C1, suggested to be formed instead of Sb8OllC12, is not an intermediate of this process. An identical mechanism is observed in air but with oxidation of Sb203 to Sb204.
Characterization of Sb2O3 subjected to different ion and plasma surface treatments
Surface and Interface Analysis, 2003
This paper presents a study of Sb 2 O 3 subjected to oxygen plasma and to ion beam bombardment (Ar + and O 2 + ions of 4 keV) by x-ray photoelectron and reflected electron energy-loss spectroscopies. Changes in stoichiometry (i.e O/Sb ratio) and oxidation state of Sb have been detected and correlated with the chemical and ballistic effects of the beams used for alteration of the Sb 2 O 3 surface. Thus, oxygen plasma treatments lead to a significant oxidation of the surface layers of this material with the formation of up to 51% Sb 5+ species as found by Sb 4d curve-fitting analysis. By contrast, O 2 + ion bombardment only produces a mild oxidation of the target with the formation of ∼13% Sb 5+ species. Argon ion bombardment induces a complex process where Sb 5+ and Sb 0 species are formed simultaneously. This result has been discussed in terms of a disproportionation reaction of the type Sb 3+ → Sb 5+ + Sb 0 . The changes in the electronic properties of the treated material are consistent with the loss upon oxidation to Sb 5+ of the valence states associated to the 5s 2 electron pair of antimony. Approximate shapes of valence bands for Sb 2 O 3 and Sb 2 O 5 pure compounds have been extracted by applying factor analysis to valence band spectra of Sb 2 O 3 subjected to different ion and plasma treatments.
Journal of Sustainable Metallurgy, 2018
As antimony is typically present in industrial and commercial products only in small amounts, the concentration of antimony in waste types is low and a limited amount of antimony is currently recycled. One product relatively rich in antimony is the metal oxide varistor (MOV) used for overvoltage protection in electric circuits. To increase the antimony concentration, the MOV was pulverized (\ 65 lm) and leached, resulting in an insoluble MOV residue containing 186 ± 2 mg/g of antimony. This work investigates the thermal decomposition and carbothermal reduction of pure metal oxides (Sb 2 O 3 , Bi 2 O 3 , and ZnO) and MOV residue. Thermogravimetric (TG) analysis was used in order to propose a temperature range in which it is possible to separate antimony oxide from the MOV residue. TG results indicate that during thermal decomposition of pure metal oxides, sublimated antimony oxide can be recovered at 650°C, leaving Bi 2 O 3 and ZnO unreacted. The addition of carbon caused mainly volatilization, with some reduction, of Sb 2 O 3 and reduction of Bi 2 O 3 to occur at nearly the same temperature, approximately 600°C. However, volatilization of Bi was not troublesome below 800°C due to slow kinetics. Thermal decomposition of antimony from the MOV residue was not possible in the temperature range studied (\ 1000°C), while carbothermal reduction to the MOV residue revealed antimony volatilization occurred near 800°C.
Structural and vibrational study of cubic Sb_ {2} O_ {3} under high pressure
2012
We report an experimental and theoretical study of antimony oxide (Sb 2 O 3) in its cubic phase (senarmontite) under high pressure. X-ray diffraction and Raman scattering measurements up to 18 and 25 GPa, respectively, have been complemented with ab initio total-energy and lattice dynamics calculations. X-ray diffraction measurements do not provide evidence of a space-group symmetry change in senarmontite up to 18 GPa. However, Raman scattering measurements evidence changes in the pressure coefficients of the Raman mode frequencies at 3.5 and 10 GPa, respectively. The behaviour of the Raman modes with increasing pressure up to 25 GPa is fully reproduced by the lattice-dynamics calculations in cubic Sb 2 O 3. Therefore, the combined analysis of both experiments and lattice-dynamics calculations suggest the occurrence of two isostructural phase transformations at 3.5 and 10 GPa, respectively. Total-energy calculations show that the isostructural phase transformations occur through local atomic displacements in which senarmontite losses its molecular character to become a three-dimensional solid. In addition, our calculations provide evidence that cubic senarmontite cannot undergo a phase transition to orthorhombic valentinite at high pressure, and that a phase transition to a β-Bi 2 O 3 type structure is possible above 25 GPa.
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2000
Antimony oxide trihalides, SbOX 3 molecules, where X =F or Cl have been produced, by means of an on-line process, using antimony trichloride, SbOCl 3 as starting material passed over heated silver oxide at 230°C. The antimony oxide trichloride SbOCl 3 formed is then reacted with sodium fluoride, NaF at 550°C to produce antimony oxide trifluoride, SbOF 3 . The products have been characterized by the IR spectra of their vapors. Low resolution gas-phase Fourier transform infrared spectra show strong bands centered at 1272 and 1217 cm − 1 , assigned to n 1 (a 1 ), the O Sb stretching fundamental of SbOF 3 and SbOCl 3 , respectively. Both observed bands show typical PQR-type structure with a strong Q-head.
Materials Research Express, 2015
In this paper, we try to give a plausible explanation to the dynamics of incorporation of sulfur element inside antimony (Sb 2 S 3 ) lattices. This incorporation has been recorded recently as a possible way for enhancing energy conversion devices performance. Some parameters, such as Urbach tailing, Faraday effect (FE) and Amlouk-Boubaker opto-thermal expansivity constants have been reported and correlated to crystallite size along with conversion performance. It has been demonstrated that latticelinked parameters' ratio compatibility can be introduced as a guide to explain the increase of the thickness-induced oxygen/sulfur substitution effect which favors such compounds' renewable energy conversion-related properties.
Journal of Crystal Growth, 2004
Antimony trioxide (Sb2O3) thin films were prepared by conventional thermal vacuum evaporation technique. Cleaned microscope glass substrates were used. The substrate temperature was varied in the range 300–573 K. X-ray diffraction, transmission electron microscopy, high-resolution transmission electron microscopy, scanning electron microscopy (SEM) and atomic force microscopy (AFM) were performed on the study of Sb2O3 thin films. The X-ray and electron diffraction analysis revealed that the Sb2O3 thin films were polycrystalline cubic structure phase with lattice parameter around a=11.1400 Å. The most preferential orientation is along (2 2 2) planes for all deposition films. The lattice parameter, grain size and microstrain in the films were calculated by X-ray patterns and correlated with substrate temperature. The grain size distributions were made from SEM micrograph. For all samples the fitted lognormal distribution is in good agreement with the histogram distribution in the whole grain size range. The mean grain size was found to increase from 46.48 to 95.56 nm when the substrate temperature was increased from 300 to 573 K. The surface topography of the Sb2O3 thin films was investigated by AFM. The roughness parameters obtained by this study was found to increase when the substrate temperature increases from 300 to 573 K.
Effect of precipitation route on the properties of antimony trioxide
Materials Chemistry and Physics, 2008
Antimony trioxide was prepared, using antimony potassium tartarate as starting material, via forward and reverse precipitation technique. The characteristics of the resulting antimony oxides were determined by BET surface area method, differential thermogravimetry analysis (DTG), X-ray diffraction (XRD), Fouriertransform infrared spectroscopy (FT-IR) and SEM. The DTG curves for all uncalcined samples showed only a single endothermic peak which indicated that the sample is antimony trioxide. Unlike forward precipitation technique which resulted in a single antimony trioxide phase which is senarmontite, reverse precipitation technique produced antimony trioxide with both senarmontite and valentinite phase. Upon calcinations at 723 K, a small amount of Sb 2 O 4 with cervantite phase was formed at the expense of Sb 2 O 3 senarmontite phase as detected from the XRD pattern and infrared spectrum of RSb. The effect of preparation route on the properties of the antimony trioxide produced was clearly demonstrated.
Antimony desinsertion reaction from SbxCoSb3−x
Journal of Applied Physics, 2011
The compound Sb x CoSb 3Àx was produced at 7.7 GPa and 550 C in a self-insertion reaction from the binary skutterudite CoSb 3. This self-insertion reaction is characterized by the collapse of some framework Sb atoms into the cages formed by the Co and Sb atoms in the skutterudite structure, as was further confirmed by Bader's analysis of maximum-entropy charge density maps obtained from synchrotron radiation x-ray powder diffraction data. The opposite reaction (i.e., Sb desinsertion, Sb x CoSb 3Àx ! CoSb 3) occurs when Sb x CoSb 3Àx is heated above 180 C at ambient pressure. This desinsertion reaction was followed by means of differential scanning calorimetry, x-ray diffraction, and electrical resistivity measurements. Differential scanning calorimetry measurements revealed the presence of two thermal events in samples rich in the Sb x CoSb 3Àx phase. An endothermic peak around 150 C was assigned to a small change in the position of the guest Sb atoms inside the cages of Sb x CoSb 3Àx. This assignment was based on the analysis of charge density maps obtained from synchrotron x-ray diffraction measurements carried out both at room temperature and at 155 C. Accordingly, the guest Sb atoms in Sb x CoSb 3Àx shift from the 12d (x,0,0) site of Im3 space group (in a position distant about 0.35 Å from the center of the cages), at room temperature, to the 2a (0,0,0) site (i.e., to the center of the cages) above 150 C. An exothermic event starting at 180 C is the thermal signature of the desinsertion of guest Sb atoms from the Sb x CoSb 3Àx skutterudite cages, as confirmed by x-ray diffraction analysis and further verified by electrical measurements. After heating to 350 C, Sb x CoSb 3Àx samples fully convert back to CoSb 3. The Sb desinsertion reaction from Sb x CoSb 3Àx follows a first order kinetics, with a transition enthalpy of approximately 21 kJ=mol and an activation energy of 83 kJ=mol.