Sesquioxides temperatures

Titanium Sesc uioxide. Ti202 has the comndum stmcture. At room temperature it behaves as a semiconductor having a small (0.2 eV) band gap. At higher temperatures, however, it becomes metallic. This is associated with marked change in the mean Ti—Ti distance. As with TiO, titanium sesquioxide, Ti202, may be made by heating a stoichiometric mixture of titanium metal and titanium dioxide powders at 1600°C under vacuum in an aluminum or molybdenum capsule. 

Va.na.dlum(III) Oxide. Vanadium(III) oxide (vanadium sesquioxide, V2O2) is a black soHd, having the comndum (AI2O2) stmcture. It can be prepared by reduction of the pentoxide by hydrogen or carbon. Air oxidation proceeds slowly at ambient temperatures, but oxidation by chlorine at elevated temperatures to give VOCl and V20 is rapid. 

Antimony Trioxide. Antimony(III) oxide (antimony sesquioxide) [1309-64-4] Sb203, is dimorphic, existing in an orthorhombic modification valentinite [1317-98-2] is colorless (sp gr 5.67) and exists in a cubic form and senarmontite [12412-52-17, Sb O, is also colorless (sp gr 5.2). The cubic modification is stable at temperatures below 570°C and consists of discrete Sb O molecules. The molecule is similar to that of P40 and As O and consists of a bowed tetrahedron having antimony atoms at each corner united by oxygen atoms lying in front of the edges. This solid crystallizes in a diamond lattice with an Sb O molecule at each carbon position. 

This paper reviews data on certain thermodynamic aspects of the nonstoichiometric Pu-0 system, which may serve as a basis for use In reactor safety analysis. Emphasis Is placed on phase relationships, vaporization behavior, oxygen-potential measurements, and evaluation of pertinent thermodynamic quantities. Limited high temperature oxygen potential data obtained above the fluorite, diphasic, and sesquioxide phases In the Pu-0 system are presented. 

It should be emphasized that very little is quantitatively known about how the total pressures of plutonium-bearing species vary with oxygen potential, stoichiometry, and temperature in the bivariant region of oxygen-deficient plutonia between the phase limits at very high temperatures. New (though limited) oxygen potential data have been obtained in our laboratory above the fluorite, diphasic, and sesquioxide phases in the Pu-0 system at 1750, 2050, and 2250 K. 

Bismuth sesquioxide, BijOj, exhibits a high oxide ion conductivity at high temperature without doping of aliovalent cations. The oxide transforms from the monoclinic... 

Cerium oxide, 74 649, 650 air/fuel conditions and, 70 50 for oxidizing iron in glass, 7 343 energy gap at room temperature, 5 596t Cerium(III) oxysulfide, 5 677 Cerium(III) phosphate, 5 677 Cerium sesquioxide, 5 675 Cerium(III) sulfide, 5 676 Cerium tetrachloride, 5 674 Cerium-zirconium oxides, 74 649 Cerius2 software, 7 629 7 385, 399, 422 76 754... 

The chemical properties of berkehum are rare earth-like character because of its half-filled 5/ subsheU and should be simdar to cerium. The element readily oxidizes to berkelium dioxide, Bk02 when heated to elevated temperatures (500°C). In aqueous solutions, the most common oxidation state is -i-3 which may undergo further oxidation to +4 state. A few compounds have been synthesized, the structures of which have been determined by x-ray diffraction methods. These include the dioxide, Bk02 sesquioxide, Bk203 fluoride,... 

At ordinary temperature, dysprosium is relatively stable in air. However, when heated with oxygen it forms dysprosium sesquioxide, Dy203. With halogens, dysprosium reacts slowly at room temperature forming dysprosium trihalides ... 

Gallium sesquioxide is precipitated in hydrated form upon neutralization of acidic or basic solution of gallium salt. Also, it is prepared by thermal decomposition of gallium salts. Gallium oxide hydroxide, GaOOH [20665-52-5] on calcinations at high temperatures yields beta- Ga203. 

Indium is stable in air at ambient temperature. At red heat, it oxidizes to indium trioxide, In20s. Three other oxides of indium are known the suboxide, In20 [12030-22], monoxide, InO [12136-26-4] and the sesquioxide, In304 [66525-54-0], which is a mixture of the trioxide and monoxide. 

Combustion in air or oxygen produces lanthanum sesquioxide. However, at ambient temperatures, when exposed to moist air, the metal forms a hydrated oxide with a large volume increase. 

At ordinary temperatures rhodium is stable in air. When heated above 600°C, it oxidizes to Rh203, forming a dark oxide coating on its surface. The gray crystalline sesquioxide has a corundom-like crystal structure. The sesquioxide, Rh203, decomposes back to its elements when heated above... 

The most stable oxidation state of thuhum is -i-3. Only the tripositive Tm3+ ion is encountered in aqueous media. The metal also forms compounds in +2 and +4 valence states, but there is no evidence of Tm2+ and Tm + existing in aqueous phase. Thuhum is relatively stable in air at ambient temperature. However, it combines with oxygen on heating forming its sesquioxide, Tm203. 

The bluish-green crystalline mass is very unstable and decomposes fairly rapidly even at the ordinary temperature, giving sulphur dioxide and sulphur. The pure substance may be preserved for several hours in a vacuum. It is hygroscopic, and on absorbing moisture first becomes brown and then deposits sulphur, with concurrent formation of sulphur dioxide, sulphuric acid and possibly other sulphur acids. It is soluble in fuming sulphuric acid, an acid rich in trioxide giving a bluish solution, whilst with less rich acids the solution is brown ordinary pure sulphuric acid causes decomposition. The colour of the brown solution is regarded by some as due to colloidal sulphur formed by partial decomposition of the sesquioxide.6... 

Chromium Pyroarsenate, Cr4(As207)3, is produced when a small quantity of chromium sesquioxide is fused at a low temperature with sodium or potassium dihydrogen arsenate.12 It yields green transparent... 

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