Sesquioxides structure

Formula weight 277.52. Yellow material the lower the ignition temperature, the more soluble in water hygroscopic when weakly ignited, nonhygroscopic when strongly ignited. M.p. about 2000°C d 7.04. C sesquioxide structure type. 

TlgO, brown to black, depending on preparative conditions. M.p. 71 rC under 1 atm. of O3 Insoluble in water, d (x-ray) 10.11. C sesquioxide structure type. 

Oxides with the Cubic Rare-Earth Sesquioxide Structure... 

The enthalpy of solution of lanthanide and actinide sesquioxides is plotted as a function of molar volume in Fig. 17.4. Molar volume was chosen as a parameter because there are three different sesquioxide structures with different coordination numbers and numbers of molecules per unit cell the plot is referenced to one mole of M (MO 15 rather than M2O3) because trichloride data are shown on a similar plot and will be discussed below. Ionic radii [44] could have been used, since these are tabulated as a function of coordination number, but often they are reliable to only two significant figures. It is evident that, for all three structure types, the enthalpies of solution of actinide sesquioxides are significantly less exothermic than for structurally similar lanthanide sesquioxides. 

From Pu onwards, sesquioxides become increasingly stable with structures analogous to those of Lu203 (p. 1238) Bk02 is out-of-sequence but this is presumably due to the stability of the f configuration in Bk. For each actinide the C-type M2O3 structure (metal CN = 6) is the most common but A and B types (metal CN = 7) are often also obtainable. 

Melles and Backer " found, from a study of the oxidation of substituted thiophenes with perbenzoic or peracetic acid, that sulfones could be obtained from polysubstituted methyl- and phenyl-thiophenes and that the presence of electron-attracting groups, such as nitro, hindered the oxidation. Oxidation of thiophene - led to a product which was formed through a Diels-Alder reaction between the intermediate thiophene sulfoxide (211) and thiophene sulfone (212) and for which two alternative structures, (213) or (214), were suggested. Similar sesquioxides were also obtained from 2- and 3-methylthiophene and 3-phenylthiophene. The structures were not proved. Bailey and Cummins synthesized thiophene-1,1-dioxide... 

Illuvial accumulation of organic matter Residual accumulation of sesquioxides Illuvial accumulation of sesquioxides Accumulation of clay Development of color or structure... 

Oxidation of these model sulfur compounds was studied without solvent to investigate the chemical structure of the products using S K-edge XANES. A solvent free tri-phase (organic/ H202aq./catalyst) was used under the described conditions. Figure 1 shows the XANES spectra from the organic and aqueous phases as well as reference materials. The thiophene oxidized to thiophene-sesquioxide [3a,4,7,7a-tetrahydro-4,7-epithiobenzo[b]-thiophene 1,1.8-trioxide ] first.. The sesquioxide solid precipitated from the solvent free reaction mixture and was identified by NMR, IR and C,H,S elemental analytical. The sesquioxide oxidized to sulfate. 2-MT and 2,5 DMT also oxidized to... 

The basic structure of carboxyethylgermanium sesquioxide, a low-toxicity y-interferon inducing agent, consists of a 12-membered ring containing six Ge tetrahedra bridged by oxygen atoms. 

FIGURE 1. Structure proposed for carboxyethyl-germanium sesquioxide (modified from Reference 12)... 

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 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 sesquisiloxanes, (RSiOi,s)n (n = 4, 6, 8, 10, 12), adopt a variety of molecular cage structures (Figure 13).404-408 The ferr-butylgermanium sesquioxide, (Bu Ge Og, has the same structure as its silicon analogue.409... 

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