No abstract available

[en] Radioactive iodine(I-131) is easily obtained by heating, at a temperature ranging from 600⁰C to 650⁰C, a tellurium oxide intermediate which was obtained by heating telluric acid or tellurium trioxide at a temperature from about 400⁰C to 560⁰C and was irradited with a neutron flux. Thus, pure I-131 is obtained without the complicated operations required in a conventional process for separation and/or purification of the product. 4 claims

[en] The domain nucleation and growth during switching process in telluric acid ammonium phosphate crystals has been investigated by nematic liquid crystal decoration technique. The domain configuration arising during polarization reversal has been discussed, considering that the type of nucleation is the controlling factor in the propagation of the domain walls. (author)

[en] The new telluric acid adduct (RbCl)₃.Te(OH)₆ was prepared by dissolving RbCl and Te(OH)₆ in the molar ratio of 3: 1 in deionized water at r.t. and slow evaporation of the solvent in air. The crystal structure of the colorless crystals was determined with single-crystal X-ray diffraction (trigonal space group: R anti 3c (no.167), a = 14.4392(8), c = 10.4301(16) A, Z = 6). In (RbCl)₃.Te(OH)₆, the rubidium atom is surrounded by five chlorine and four oxygen atoms in form of an irregular tricapped trigonal prism.E ach tellurium atom is octahedrally surrounded by six oxygen atoms. The Te(OH)₆ octahedra and the RbCl₅O₄ polyhedra are linked to a dense three-dimensional network which is additionally strengthened by hydrogen bonds. (orig.)

No abstract available

[en] Carrier-free ¹³¹I suitable for medical use was produced from tellurium dioxide using the wet distillation method. Five gram samples of TeO₂ were irradiated intermittently in the beam port (BX-2) of the Philippine Research Reactor up to 250 hours (based on reactor operation of 12 hours a day, Monday to Friday). The irradiated tellurium dioxide was then dissolved in sodium hydroxide. An oxidant was added and after a predetermined amount of sulfuric acid was added, I₂ 131 was distilled off and subsequently reduced in a solution of sodium hydroxide. An oxidant was added and after a predetermined amount of sulfuric acid was added, ¹³¹I₂ was distilled off and subsequently reduced in a solution of sodium hydroxide trickling in a vertical absorber filled with glass beads. The gamma spectrum showed peaks due only to ¹³¹I and half-life determination followed for more than five half-lives giving an average value of 8.03 days for three runs. The absence of tellurium in the product was confirmed by the method of Gopal and Frapart having a sensitivity of ug. A distilling efficiency of 50-60% can be attained with two one-hour distillations. Although the last runs gave recoveries ranging from 30-40% it is believed that higher recoveries could be obtained with better sealing. If a continuous glass design could be used, utlizing a little vacuum, higher recoveries are expected at minimum exposure to the worker. As in telluric acid, favorable distillation depends primarily on pH of the solution and distilling temperature. For TeO₂, evolution of ¹³¹I seems to be maximum at pH 2.5 and there abouts and recovery of distillable ¹³¹I almost maximum after two and one half hours of distillation. In fact 90% of the recoverable activity can be obtained after two hours such that a third distillation is practically needless

No abstract available

[en] A new condensation inorganic polymer, Na(TeW₁₂O₄₀)24H₂O, has been prepared and characterised on the basis of analytical and molecular weight determinations. The thermal depolymerization of the product has been studied extensively. (author)

No abstract available

[en] The heat capacities of dissociation for carbonic, bicarbonate, phosphoric, biphosphate, silicic, nitric, boric and bisulfate oxy-acids have been evaluated at temperatures up to 300 C using published dissociation constants, heat capacities and a model which explicitly accounts for both electrostatic and nonelectrostatic contributions to the thermodynamic properties of dissociation. The heat capacities calculated are independent of the entropies of dissociation or the chemical characteristics of the acids, and are the same for all acids of a given dissociation type (i.e. 1st, 2nd, etc.). The average deviation between measured and calculated log Ksub(T)'s is less than 0.05 log units in the temperature range from 25 to 300 C. Dissociation constants for acetic acid can be accurately calculated using the oxy-acid heat capacity expression. The heat capacities are used to calculate dissociation constants for the oxy-acids of Cr(VI), N(III), S(IV), S(II), Se(IV), Se(VI), As(III), As(V), Te(VI), Cl(I), Cl(III), I(V) and C₁-C₃ aliphatic acids to temperatures of 300 C. (author)