Tellurium oxide fluorides

Te2Fio, and oxide fluorides, e.g. TeFjOTeFs, are also formed during the fluor-ination of tellurium oxides, tellurium, organic derivatives Tellurium forms organic derivatives in the +2 and +4 slates. The +2 compounds are similar to divalent sulphur derivatives although less stable. Tellurium(IV) derivatives are comparatively unstable. 

Tellurium (VI) fluoride, 1 121 Tellurium(IV) oxide, 3 143 Tellurium (II) xanthates, 4 91 Tetrabutylammonium dibromo-bromate(I), 5 177 Tetrabutylammonium dichloro-iodate(I), 5 174... 

TeCl5(NHi)2 Ammonium hexa-chlorotellurate(IV), 2 189 TeFe Tellurium(VI) fluoride, 1 121 TeOa Tellurium(IV) oxide, 3 143 TeOeHe Telluric acid, 3 145, 147 Te(S2CN(CH,)2)2 Tellurium (II) dimethyldithiocarbamate, 4 93 Te(S2CN(C2H5)2)2 Tellurium (II) diethyldithiocarbamate, 4 93 Te(S2COCH,)2 Tellurium(II) methylxanthate, 4 93 Te(S2COC2H6)2 Tellurium(II) eth-ylxanthate, 4 93... 

Magnesium Air, beryllium fluoride, ethylene oxide, halogens, halocarbons, HI, metal cyanides, metal oxides, metal oxosalts, methanol, oxidants, peroxides, sulfur, tellurium... 

Pentafluorophenylditelluridc yields 79-80% pentafluorophenyltellunum tri fluoride on treatment with fluorine or xenon difluoride [105] The fluonnated tetravalent tellurium can be further oxidized to hexavalent tellurium with either xenon difluoride [/22] or fluorine [123]... 

The magnetic criterion is particularly valuable because it provides a basis for differentiating sharply between essentially ionic and essentially electron-pair bonds Experimental data have as yet been obtained for only a few of the interesting compounds, but these indicate that oxides and fluorides of most metals are ionic. Electron-pair bonds are formed by most of the transition elements with sulfur, selenium, tellurium, phosphorus, arsenic and antimony, as in the sulfide minerals (pyrite, molybdenite, skutterudite, etc.). The halogens other than fluorine form electron-pair bonds with metals of the palladium and platinum groups and sometimes, but not always, with iron-group metals. 

In contrast to the cathodic reduction of organic tellurium compounds, few studies on their anodic oxidation have been performed. No paper has reported on the electrolytic reactions of fluorinated tellurides up to date, which is probably due to the difficulty of the preparation of the partially fluorinated tellurides as starting material. Quite recently, Fuchigami et al. have investigated the anodic behavior of 2,2,2-trifluoroethyl and difluoroethyl phenyl tellurides (8 and 9) [54]. The telluride 8 does not undergo an anodic a-substitution, which is totally different to the eases of the corresponding sulfide and selenide. Even in the presence of fluoride ions, the anodic methoxylation does not take place at all. Instead, a selective difluorination occurs at the tellurium atom effectively to provide the hypervalent tellurium derivative in good yield as shown in Scheme 6.12. 

Ceric ammonium sulfate, 5 674 Ceric fluoride, 5 674 Ceric hydroxide, 5 676 Ceric oxide, 5 670, 675 Ceric rare earths (RE), 74 631 Ceric sulfate, 5 674 Ceric sulfate method, for tellurium determination, 24 415 Cerium (Ce), 5 670-692 74 630, 63 It, 634t. See also Cerium compounds analysis, 5 679-680 color, 7 335... 

The platinum metal chalcogenides in general are easier to prepare than the corresponding oxides. Whereas special conditions of temperature and pressure are required to prepare many of the oxides, the platinum metals react most readily with S, Se, and Te. A number of additional differences concerning the chemistry of the chalcogenides and the oxides are summarized as follows The metal—sulfur (selenium, tellurium) bond has considerably more covalent character than the metal-oxygen bond and, therefore, there are important differences in the structure types of the compounds formed. Whereas there may be considerable similarity between oxides and fluorides, the structural chemistry of the sulfides tends to be more closely related to that of the chlorides. The latter compounds... 

Fluorination with elemental fluorine diluted 1 20 with nitrogen was used to prepare pentafluorophenyl tellurium trifluoride from bis[pentafluorophenyl] ditellurium at — 60° with fluorotrichloromethane as the reaction medium. The yield in this reaction was 80% 4-Methoxyphenyl tellurium trifluoride was obtained by electrochemical oxidation of the diaryl ditellurium in 0.5 M hydrofluoric acid at platinum electrodes2. Bisfpentafluoroethyl] ditellurium and chlorine fluoride (1 6) reacted at — 78° to give pentafluoroethyl tellurium trifluoride, a white solid melting at 95°3. The same compound was obtained with xenon difluoride as the fluorinating agent and melted at 143°4. 

Uranium can be analysed as the hexafluoride, but the procedure requires modification of the chromatographic apparatus, nickel coating of metallic parts and nickel filaments in the katharometer [606], Tin in zirconium—tin alloys can be analysed as the chloride, prepared by treatment with chlorine [607]. Selenium and tellurium are converted into fluorides by treatment of their oxides with xenon difluoride [608]. 

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