Tellurate

Abstract: Woolfolk, C. A. (University of Washington, Seattle) and H. R. Whiteley. Reduction of inorganic compounds with molecular hydrogen by Micrococcus lactilyticus. I. Stoichiometry with compounds of arsenic, selenium, tellurium, transition and other elements. J. Bacteriol. 84:647–658. 1962.—Extracts of Micrococcus lactilyticus (Veillonella alcalescens) oxidize molecular hydrogen at the expense of certain compounds of arsenic, bismuth, selenium, tellurium, lead, thallium, vanadium, manganese, iron, copper, molybdenum, tungsten, osmium, ruthenium, gold, silver, and uranium, as well as molecular oxygen. Chemical and manometric data indicate that the following reductions are essentially quantitative: arsenate to arsenite, pentavalent and trivalent bismuth to the free element, selenite via elemental selenium to selenide, tellurate and tellurite to tellurium, lead dioxide and manganese dioxide to the divalent state, ferric to ferrous iron, osmium tetroxide to osmate ion, osmium dioxide and trivalent osmium to the metal, uranyl uranium to the tetravalent state, vanadate to the level of vanadyl, and polymolybdate ions to molybdenum blues with an average valence for molybdenum of +5. The results of a study of certain other hydrogenase-containing bacteria with respect to their ability to carry out some of the same reactions are also presented.

Abstract: Infrared analysis showed that the bonding habit of oxyanions with freshly precipitated hydrous ferric oxides depends upon the nature of the anion and its hydration level. Monovalent oxyanions adsorb through an electrostatic interaction with the hydrated hydrous oxide surface. All divalent oxyanions, with the exception of tellurate, coordinate directly with surface iron cations. Tellurate, an octahedral anion, apparently penetrates and incorporates in the hydrous oxide structure. The symmetry of the free anion has a significant role in determining the configuration of the resultant complex. For anions of the same charge, those with tetrahedral geometry (in uncoordinated states) show a higher degree of specificity for the surface than the trigonal planer anions. Without exception, each bidentate bridging complex forms by replacement of protonated and unprotonated hydroxyls. With the anion geometry and the charge being equal, the sus- pension pH determines the adsorption capacity of the hydrous oxide.

Abstract: A simple hydrothermal reduction method, employing sodium tellurate (Na2TeO4·2H2O) as tellurium source and formamide (HCONH2) as a reductant, was used to prepare and investigate tellurium nanotubes. The diameters of the nanotubes range from 200 to 600 nm and their lengths from 4 to 15 μm. Unlike studies reported previously,1,2 a series of electron microscopy characterization results suggests that the growth of tellurium nanotubes under the present experimental conditions is governed by a nucleation−dissolution−recrystallization growth mechanism: sphere-like tellurium nanoparticles initially formed in the hydrothermal system; the sphere-like nanoparticles were gradually dissolved to generate free tellurium atoms in the solution; these tellurium atoms were renewedly transferred onto the surfaces of the sphere-like nanoparticles and evolved into groove-like nanorods; the groove-like nanorods could be grown into tellurium nanotubes eventually.