Sesquioxides forms

B. C. Dutt and S. N. Sen found that when nitric oxide is passed into a suspension of barium dioxide in water, barium nitrite, not nitrate, is formed. P. Sabatier and J. B. Senderens observed no change when nitric oxide is passed over Cuprous Oxide at 500°. H. A. Auden and G. J. Fowler observed that dry nitric oxide and Silver oxide, at ordinary temp., form silver and silver nitrate P. Sabatier and J. B. Senderens also obtained silver and silver nitrite by passing nitric oxide into water with silver oxide in suspension. C. F. Schonbein found gold oxide is reduced by moist nitric oxide, forming nitrous acid. P. Sabatier and J. B. Senderens found that titanium sesquioxide forms white titanic oxide when heated in an atm. of nitric oxide and that stannous oxide below 500° burns in an atm. of nitric oxide, forming stannic oxide. If nitric oxide be passed into water with lead dioxide in suspension, the water is coloured, and in about 3 hrs., lead nitrite and nitrate are formed, and later, rhombic crystals of a basic nitrite. B. C. Dutt and S. N. Sen said that the nitrate is formed by the action of the dioxide on the nitrite. Lead dioxide is reduced to lead oxide by nitric oxide at 315°, and H. A. Auden and G. J. Fowler found that the reaction begins at 15°, when a basic lead nitrite is... 

Both of these oxides are present on nearly any piece of plutonium metal that has undergone some corrosion. Under normal conditions, the outside smface of Pu contains PUO2, while the sesquioxide forms between the PUO2 layer and the metal. The relative amount of these phases is dictated by the partial pressme of oxygen in the atmosphere. 

Cheluviation. Cheluviation involves the transport of organo-metallic complexes (i.e., chelates) of iron and aluminum. Once transported to the lower horizon B, the iron and aluminum precipitate as iron and aluminum sesquioxides forming colored spodic horizons denoted B,. 

Oxides of the lighter actinides include AC2O3, which exists only in the A-type sesquioxide form (discussed later), Th02, which has the fluorite structure, and PajOj, which has five crystal modifications [2], none of which have been elucidated in detail. This last compound can be reduced to Pa02 having the fluorite arrangement. 

In the sohd phase the most stable forms of Mn (ITT) are manganese sesquioxide [1317-34-6] M1I2O2, and its hydrate Mn202 and manganese... 

Manganese(III) Oxides. The sesquioxide, Mn202, exists in dimorphic forms. The a-Mri202 exists in nature as the mineral bixbyite. 

Binary Compounds. The fluorides of indium are IrF [23370-59-4] IrF [37501-24-9] the tetrameric pentafluoride (IiF ) [14568-19-5], and JIrFg [7789-75-7]. Chlorides of indium include IrCl, which exists in anhydrous [10025-83-9] a- and p-forms, and as a soluble hydrate [14996-61-3], and IrCl [10025-97-5], Other haUdes include IrBr [10049-24-8], which is insoluble, and the soluble tetrahydrate IrBr -4H20 IrBr [7789-64-2]-, and Irl [7790-41-2], Iridium forms indium dioxide [12030-49-8], a poorly characteri2ed sesquioxide, 11203 [1312-46-5]-, and the hydroxides, Ir(OH)3 [54968-01-3] and Ir(OH) [25141-14-4], Other binary iridium compounds include the sulfides, IrS [12136-40-2], F2S3 [12136-42-4], IrS2 [12030-51 -2], and IrS3 [12030-52-3], as well as various selenides and teUurides. 

Forsterite. Pure forsterite is rare in nature. Most natural magnesium orthosiUcates form soHd solutions of fayaUte, Fe2Si04, and forsterite. Forsterite refractories are usually made by calcining magnesium siUcate rock such as dunite, serpentine, or oHvine with sufficient magnesia added to convert all excess siUca to forsterite and all sesquioxides to magnesia spinels. 

The oxide monobutyltin oxide [51590-67-1J, is a sesquioxide, C H SnO from which it is difficult to remove the last traces of water. It is an infusible, insoluble, amorphous white powder that forms when butyltin trichloride is hydrolyzed with base. The partially dehydrated material, butylstaimoic acid [2273-43-0] is slightly acidic and forms alkaH metal salts. These salts, ie, alkaH metal alkylstaimonates, form when excess alkaH is used to hydrolyze the organotin trichloride ... 

Alternative methods of production include reduction of HO2 with magnesium, which yields TiO only. When titanium monoxide is heated in air at 150—200°C, titanium sesquioxide, Ti202, forms, and at 250—350°C, it changes to Ti O. ... 

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. 

Cerium Oxide. The most stable oxide of cerium is cerium dioxide [1306-38-3] Ce02, also called ceria or ceric oxide. When cerium salts are calcined in air or if oxygen is present, this tetravalent Ce(IV) oxide is formed, cerium sesquioxide [1345-13-7] can be prepared in strongly reducing... 

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... 

This choice of space group is further substantiated by Zachariasen s data for the other substances as well as bixbyite. His reproduced Laue photographs of Tl .03 and of bixbyite show no spots due to 071, 017, 091, 019, 0.11.1 or 0.1.11, although planes of these forms were in positions favorable to reflection, while the powder data show that 031, 013, 073, and 037 gave no reflections for any of the sesquioxides studied. Zachariasen s rejection of ZJ arose from his... 

During the lifetime of a root, considerable depletion of the available mineral nutrients (MN) in the rhizosphere is to be expected. This, in turn, will affect the equilibrium between available and unavailable forms of MN. For example, dissolution of insoluble calcium or iron phosphates may occur, clay-fixed ammonium or potassium may be released, and nonlabile forms of P associated with clay and sesquioxide surfaces may enter soil solution (10). Any or all of these conversions to available forms will act to buffer the soil solution concentrations and reduce the intensity of the depletion curves around the root. However, because they occur relatively slowly (e.g., over hours, days, or weeks), they cannot be accounted for in the buffer capacity term and have to be included as separate source (dCldl) terms in Eq. (8). Such source terms are likely to be highly soil specific and difficult to measure (11). Many rhizosphere modelers have chosen to ignore them altogether, either by dealing with soils in which they are of limited importance or by growing plants for relatively short periods of time, where their contribution is small. Where such terms have been included, it is common to find first-order kinetic equations being used to describe the rate of interconversion (12). 

Vanadium forms numerous oxides, the most important of which are vanadium monoxide, vanadium sesquioxide, vanadium dioxide and vanadium pentoxide. In the earlier examples (e.g., oxides of chromium and of niobium) the enthalpy values for the aluminothermic reduction of each of the oxides was given for the purpose of illustration. Normally, the consideration can be restricted to only those oxides which are readily obtained and which can be handled freely without any special or cumbersome precautions. In the case of vanadium for example, it is sufficient to consider the reduction of the sesquioxide (V203) and the pentoxide (V2Os). The pertinent reactions are ... 

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 ... 

When heated in oxygen or air, the metal (in lump form) slowly oxidizes forming erbium sesquioxide, ErsOs. 

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. 

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. 

Dissolution of phosphorus sesquioxide in water also forms phosphorus acid. When shaken with ice water, phosphorus acid is the only product... 

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... 

Treating the sesquioxide with alkali first forms a yellow precipitate of pen-tahydrate, Rh203 5H2O, soluble in acid and excess alkali. In excess alkali a black precipitate of trihydrate, Rh203 3H20 is obtained. The trihydrate is insoluble in acids. 

Samarium sesquioxide dissolves in mineral acids, forming salts upon evaporation and crystallization ... 

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. 

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