Tellurates glasses

The incorporation of network modifier lead ions into the vanadate-tellurate glasses enhances the breaking of axial Te-O-Te linkages in the [Te04] trigonal bypiramidal structural units. As a consequence, three-coordination tellurium is formed and accumulated. The band centered at about 750cm-i indicates the presence of the [TeOs] structural units [17,... 

The measured UV-VIS absorption spectra of the lead and samarium-vanadate-tellurate glasses are shown in Fig. 3. The spectra show that the maxima of the absorption are located in the UV region for all investigated glasses containing PbO or Sm203. 

S. Rada, E. Culea, M. Culea, Borate-Tellurate Glasses An Alternative of Immobilization... 

Tetraphenylarsonium Tris[0-ethyl dithiocarbonato]tellurate(II)2 580 mg (4.00 mmol) of potassium 0-ethyl dithiocarbonate and 1.68 g (4.00 mmol) of tetraphenylarsonium chloride are dissolved in 40 ml of warm methanol, 1.48 g (4.0 mmol) of solid tellurium bis[0-ethyl dithiocarbonate] are added, the mixture is stirred for a few minutes, and then filtered through a fine glass frit into a flask cooled at — 10°. The filtrate is stored in a freezer overnight, the yellow crystals are collected, and recrystallized from warm (45°) methanol yield 0.25 g (7%) m.p. not reported. 

Colorless gas. Repulsive odor, mp —37.6°. Sublimes at — 38,9°, Critical temperature 83°. d (solid —191°) 4.006 d (liq —10°) 2.499. Not as inert chemically as SeF( and SF, because the covalence maximum of tellurium is higher than 6. Slowly absorbed by water with hydrolysis to telluric acid, H6TeOt more quickly hydrolyzed by aq KOH. Does not attack glass when pure. Corrodes mercury. 

CHEMICAL PROPERTIES stable under ordinary conditions of use and storage hydrolyzes slowly in water to telluric acid (H606Te) more quickly hydrolyzed by aqueous potassium hydroxide when pure, does not attack glass corrosive to mercury not as chemically inert as sulfur hexafluoride (SF(,) and selenium hexafluoride (SeFs) because the maximum covalence of tellurium is greater than six FP (NA) LFLZUFL(NA) AT(NA) HC(NA) HF(-1318.0 kJ/mol gas at 25 C) Tc (83 C, 181.4 ). 

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