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Tellurium tellurates

Oxides of composition TeO, TeOa and Te03 are known, as well as a fourth compound, Tea07, which appears to be a basic tellurium tellurate,... [Pg.369]

The Tellurates.—It is an interesting fact that tellurium dioxide dissolves in a solution of telluric acid the solution on slow evaporation gives crystals of telluric acid together with granules of a tellurium tellurate, 2Te02.Te03 or Te307.5... [Pg.387]

TEL, Et4pb. Lead tetraethyl, fellurates Formally salts containing oxy-anions of tellurium. Tellurales(VI) contain octahedral [TeO ] " species and derivatives of these. Tellurates(IV), tellurites, contain [TeOa] " species. [Pg.386]

Tellurium dioxide, Te02- Obtained by burning Te in air or heating tellurales(IV). Has rutile or brookile structures. Almost insoluble in water but gives tellurates(IV) with bases and, e g., TeCl4 with acids. [Pg.387]

Selenium and tellurium react similarly, forming selenides and selenates(IV), and tellurides and tellurates(IV) respectively. Like the sulphide ion, S , the ions Se and Te form polyanions but to a much lesser extent. [Pg.267]

Tellurium trioxide, TeOa, is an orange yellow powder made by thermal decomposition of telluric(VI) acid Te(OH)g. It is a strong oxidising agent which will, like H2Se04, oxidise hydrogen chloride to chlorine. It dissolves in hot water to give telluric(VI) acid. This is a weak acid and quite different from sulphuric and selenic acids. Two series of salts are known. [Pg.305]

Both selenium hexafluoride and tellurium hexafluoride are more reactive than sulphur hexafluoride. Tellurium hexafluoride is slowly hydrolysed by water to telluric) VI) acid and on heating it decomposes to fluorine and the tetrafluoride. [Pg.306]

Crystalline tellurium has a silvery-white appearance, and when pure exhibits a metallic luster. It is brittle and easily pulverized. Amorphous tellurium is found by precipitating tellurium from a solution of telluric or tellurous acid. Whether this form is truly amorphous, or made of minute crystals, is open to question. Tellurium is a p-type semiconductor, and shows greater conductivity in certain directions, depending on alignment of the atoms. [Pg.120]

Fluor-jod, n. iodine fluoride, -kalium, n. potassium fluoride, -kalzium, n. calcium fluoride, -kiesel, m. silicon fluoride, -kie-selsaure,/. fluosilicic acid, -kohlenstoff, m. carbon fluoride, -lithium, n. lithium fluoride. -metall, n. metallic fluoride, -natrium, n. sodium fluoride, -phosphat, n. fluophosphate. -phosphor, m. phosphorus fluoride, -salz, n. fluoride, -schwefel, m. sulfur fluoride, -selen, n. selenium fluoride, -silber, n. silver fluoride, -silikat, n. fluo-silicate. -silizium, n. silicon fluoride, -sili-ziumverbindung, /. fluosilicate. -tantal-sMure, /. fluotantalic acid, -tellur, n. tellurium fluoride, -titan, n. titanium fluoride, -toluol, n. fluorotoluene, fluotoluene. [Pg.160]

Tellur-verbindung, /. tellurium compound, -vorlegierung,/. tellurium prealloy, -wasser-stoff, m. hydrogen telluride. -wasserstoff-sSure, /. hydrotelluric acid (hydrogen telluride). -wismut, n. bismuth telluride. [Pg.443]

The synthesis of the tellurium analogues of (24) and (25) requires a different approach, since it is not possible to prepare the necessary amido precursors in significant yields by telluration of [ BuN(H)P( U-N Bu)2PN(H) Bu]. However, the prior hthiation of this P(III)/P(III) system to give (7) followed by reaction with elemental tellurium generates the dianion (24, E = Te) as its dihthium salt (Eq. 5) [37] ... [Pg.151]

Te (tellurium, brown black, amorphous), Te02 (tellurous anhydride, white), Te02 hydr. (tellurous acid, H2Te03 or Te02-H20, white, amorphous), TeOs hydr. (orthotelluric acid, H6Te06 or Te03 3H20, colorless, cubic or monoclinic). [Pg.65]

Lingane and Niedrach have claimed that the h-VI states of tellurium (or selenium) are not reduced at the dropping electrode under any of the conditions of then-investigation however, Norton et al. [42] showed that under a variety of conditions, samples of telluric acid prepared by several different procedures do exhibit well-defined (though irreversible) waves, suitable for the analytical determination of the element. The reduction of Te(H-VI) at the dropping electrode was found coulometri-cally to proceed to the -II state (whereas selenate, Se(-i-VI), was not reduced at the dropping electrode in any of the media reported). [Pg.72]

The electrodeposition of tellurium and silver has been investigated in dilute aqueous solutions of tellurous acid and Ag " ions (concentrations in the order of 10 to 10 " M) in 0.1 M HCIO4 [164], In particular, cyclic voltammetry experiments were conducted with rotating glassy carbon disk electrodes in baths with various concentration ratios of Ag(I) and Te(IV) precursors, and their outcome was discussed in terms of the voltammetric features. For a Ag(I)/Te(IV) ratio close to 0.8, formation of quasi pure silver telluride, Ag2Te, was reported. The authors, based on their measurements and on account of thermodynamic predictions, assumed that silver is deposited first on the electrode (Ag" + e Ag), and then Te(IV) is reduced on the previous silver deposit with formation of Ag2Te according to the reaction... [Pg.114]

In addition to the telluration of a silylene, another unique synthetic route has been developed for the silicon-tellurium double bond system. Recently, it has been reported that the exhaustive reduction of an overcrowded dibromosilane Tbt(Dip)SiBr2 (61) with an excess amount (more than 4 equiv.) of lithium... [Pg.139]

Oxyacids containing selenium and tellurium are known, but they and their salts are generally less important than the sulfur compounds. When selenium and tellurium halides hydrolyze, the solutions contain selenous and tellurous acids. [Pg.542]

A new structure type is found for Ag2Hg(Se03)2. Both Ag+ and Hg2+ ions are in octahedral coordination in this compound.137 The polyhedra are linked by the pyramidal shaped selenite anions.138 In the crystal structure of the red tellurate Ag2Hg2(Te04)3, the tellurium atoms are in octahedral coordination of oxygen atoms, and the octahedra are linked to infinite chains running along the u-axis. [Pg.364]

Unlike selenium there is no required biological role for tellurium in bacteria or plants that has been determined however, this may ultimately not be the whole story.111 Selenium was only viewed as a toxic metalloid with no necessary role for metabolism until at least the 1950s see above. While tellurite is less soluble than tellurate in aqueous solution, in general tellurite is probably more toxic to most organisms.190 The non Te-resistant wild type E. coli bacterium (Gramnegative) has MICs of 1 to 3 ppm for tellurite and tellurate.144,191,192 Tellurite is used to enrich and select for Staphylococcus aureus.169,193,194... [Pg.702]

As with selenium analysis, HGAAS also finds a place in Te determination. Basnayake et al. amended cultures of P. fluorescens K27 with 0.1 mM tellurite and, after 92-h growth, determined that approximately 34% of added Te was present as either precipitated, elemental Te in/or on centrifuged cells the balance of added Te remained in solution.190 In this same study, GC/MS was used for determination of DMTe in the same facultative anaerobe amended with tellurate.190 Earlier, GC/MS was used to analyze the headspace of a tellurium-resistant fungus amended with tellurite.215 This last is one of the few reports of the detection of dimethyl ditelluride in microbial headspace (see below). [Pg.704]

The pure form of tellurium burns with a blue flame and forms tellurium dioxide (TeO ). It is brittle and is a poor conductor of electricity. It reacts with the halogens of group 17, but not with many metals. When it reacts with gold, it forms gold telluride. Tellurium is insoluble in water but readily reacts with nitric acid to produce tellurous acid. If inhaled, it produces a garlic-like odor on one s breath. [Pg.240]


See other pages where Tellurium tellurates is mentioned: [Pg.442]    [Pg.783]    [Pg.783]    [Pg.703]    [Pg.442]    [Pg.783]    [Pg.783]    [Pg.703]    [Pg.386]    [Pg.387]    [Pg.387]    [Pg.388]    [Pg.74]    [Pg.397]    [Pg.442]    [Pg.442]    [Pg.443]    [Pg.116]    [Pg.9]    [Pg.13]    [Pg.14]    [Pg.72]    [Pg.140]    [Pg.353]    [Pg.354]    [Pg.703]    [Pg.704]    [Pg.705]    [Pg.923]    [Pg.924]    [Pg.305]    [Pg.158]   
See also in sourсe #XX -- [ Pg.239 ]




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