Amorphous rapid heating

Occurs in two forms, alpha form—a colorless amorphous powder, and beta form—a reddish-brown crystal density 6.95 g/cm (alpha form) and 8.15 g/cm (beta form) decomposes on rapid heating at 900°C sublimation temperature 1,559°C insoluble in water and alkalis dissolves in mineral acids. 

Reaction with amorphous silicon at 900°C, catalyzed by steam produces cadmium orthosilicate, Cd2Si04. The same product also is obtained by reaction with sdica. Finely divided oxide reacts with dimethyl sulfate forming cadmium sulfate. Cadmium oxide, upon rapid heating with oxides of many other metals, such as iron, molybdenum, tungsten, titanium, tantalum, niobium, antimony, and arsenic, forms mixed oxides. For example, rapid heating with ferric oxide at 750°C produces cadmium ferrite, CdFe204 ... 

As for most of the zeolites with very open structure, crystallization of ZSM-20 occurs in a rather low temperature range (90-120°C), in static conditions, and is complete after about 10-15 days heating.Longer crystallization times, higher temperatures or agitation ineluctably lead to the formation of other dense or amorphous phases, that also co-crystallize with zeolite Y (44.451. More precisely, a rapid heating of the final gel above 100°C (130 or 170°C) resulted in the formation of zeolite Beta (see below). It was also observed that at these temperatures ZSM-20 initially formed at 100°C transforms into amorphous phase, probably also further precursor to Beta (32). 

DOT UN 1638 mf Hgl mw 327.49 PROP Heavy, odorless, yellow, tetragonal crystals or amorphous powder. D 7.70, mp 290° when rapidly heated (partial decomp). Insol in water, ale, and ether sol in solns of mercurous or mercuric nitrates. Protect from light. IDLH 10 mg/m (as Hg). 

Monohydrate, C,7H]9NO,HjO, usually found in the crystalline form, but die amorphous or freshly pptd form is more sol. The following data are For the usual cryst form orthorhombic, sphenoidal prisms, needles from methanol. Dec 254-256 with rapid heating- Darkens on exposure to light. Loses water at 130. df 1.32. [< ) — 132 (methanol) pKb at 20 = 6.13 pKa 9.85. pH of satd soln, 8.5. uv max in acid 285 noi in alkali 29S nm. One gram dissolves in about 5000 ml water, 1100 ml boiling water, 210 ml alcohol, 98 ml boiling ale. 1220 ml chloroform. 6250 ml ether. 114 ml... 

One part of p-tolylphosphimc acid, five parts of concentrated nitric acid and seven parts of fuming nitric acid are heated together for three hours on a water-bath, then poured into a large volume of w ater. The dinitro-acid is extracted from the solution by ether, from which solvent it ciy stallises in yellow plates, M pt. 251° C., exploding on rapid heating. The barium salt crystallises with twm molecules of wmter, the first of which is eliminated at 110° C. and the second wuth difficulty at 180° C. the lead salt is a yellowy amorphous pow der. 

Rapid heating to about 700°C (e.g. by flame spraying) of an aqueous mixture of chromic and phosphoric acids will produce anhydrous chromium phosphate (5.83) [41], This material is an amorphous purple-grey powder which transforms irreversibly on further heating to crystalline varieties and eventually to the oxide ... 

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