Sesquioxide preparation

The best characterized einsteinium oxide is the cubic (C-type) sesquioxide, prepared by calcining nanograms of a nitrate salt and rapidly analyzing the product by electron diffraction (Haire and Baybarz 1973). A monoclinic form of the sesquioxide was observed when thin films of einsteinram metal were oxidized in oxygen-containing atmospheres at temperatures of 800 1000°C (the direct oxidation of other actinide metals can also yield the monoclinic form of their sesquioxides at temperatures lower than that required for transformation of their C- to the B- forms). This low temperature for the monoelinic form of einsteinium sesquioxide is therefore not comparable to the established transition temperatures reported for the other actinide sesquioxides. The... 

Lead Sesquioxide. Lead sesquioxide (lead trioxide), Pb202, is an amorphous, orange-yeUow powder soluble ia cold water. It decomposes ia hot water and ia acids to lead salts plus Pb02. Lead sesquioxide can be prepared from lead dioxide by hydrothermal dissociation (43). 

Lead sesquioxide is used as an oxidation catalyst for carbon monoxide ia exhaust gases (44,45) (see Exhaust control), as a catalyst for the preparation of lactams (46) (see Antibiotics, P-lactams), ia the manufacture of high purity diamonds (47) (see Carbon, diamond-natural), ia fireproofing compositions for poly(ethylene terephthalate) plastics (48), ia radiation detectors for x-rays and nuclear particles (49), and ia vulcanization accelerators for neoprene mbber (50). 

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. 

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... 

Figure 3. Moisture concentration (ppm H2O) in the hydrogen carrier gas as a function of time during the preparation of the plutonium sesquioxide sample by hydrogen reduction at 2250 K.

Several other useful modifications of calciothermic reduction have been successfully developed for the preparation of this neodymium-bearing magnetic alloy. One of these is reduction-extraction which involves the reduction of neodymium sesquioxide (Nd203) with calcium in a molten calcium chloride-sodium chloride salt bath at 750 °C and the simultaneous extraction of the reduced metal into a molten neodymium-zinc or neodymium-iron alloy pool. The neodymium-zinc alloy product is treated in vacuum to remove zinc and produce neodymium metal, while the neodymium-iron alloy is itself the end product of... 

Arsenic sesquioxide may be prepared by heating arsenic trioxide with hydrogen sulfide ... 

Europeum metal is prepared from the europium sesquioxide obtained above by the reduction with lanthanum or cerium. The oxide is heated under a vacuum in a tantalum crucible with excess lanthanum turning. Europeum volatilizes and collects as a bright crystalline condensate on the wall of the crucible. It is stored and handled in an inert atmosphere, as the finely divided metal is flammable. 

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. 

Samarium sesquioxide is used in optical and infrared absorbing glass to absorb infrared radiation. Also, it is used as a neutron absorber in control rods for nuclear power reactors. Tbe oxide catalyzes dehydration of acychc primary alcohols to aldehydes and ketones. Another use involves preparation of other samarium salts. 

Prussian blue is regarded as a compound of three equivalents of ferroeyanogen with two of iron, and its composition is therefore expressed by the formula 8 Cfy -j- 2 Fea, or Fe, Cys, It is formed whenever a salt of sesquioxide of iron is added to a soluble metallio ferrocyanide. The usual method is to precipitate a solution of sesquiehloride or sesquinitrate of iron by ferrocyanide of potassium and In point qf fact a very important part of its manufacture consists in the preparation of this latter salt, which will now be described. 

Sesquioxide of Chromium—chrome green—Cr, 0 — is generally prepared for potters use by calcining a mixture of equal parte of chromate of potessa and sulphur in a close earthenware crucible at a Ted heat, the green moss which is produced being well washed to dissolve out the sulphate and sulphide of potassium. The oxide of chromium which remains ia further purified by repeated elutriation. 

Sesquioxide of Iron—Fe 0.—This is prepared by the calcination of green vitriol, upon the purity of which the brilliancy of the color in a great measure depends, For the calcination a thick cast-iron vessel or earthenware retort is required. During the operation the 5... 

An application has been suggested for this sesquioxide in the preparation of certain organic dyes containing sulphur.8... 

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