Chromium compounds decomposition

Decomposition of the metal ammines have probably been most extensively investigated. Some qualitative features of the thermal decomposition of metal ammine compounds are conveniently illustrated [1116— 1118] by the somewhat contrasting behaviour of the compounds [Cr(NH3)6]X3 and [Co(NH3)6]X3 where X is Cl- or Br . During decomposition of the chromium compound, the oxidation number of the metal remains unchanged, viz. 

The corresponding chromium compounds [Cr(en)3]X3 evolve ethylenediamine [1131] and the values of E determined using non-isothermal measurements were 105 and 182 kJ mole 1 for X = Cl" and SCN", respectively. Hughes [1132] reported a value of E = 175 kJ mole"1 for X = Cl" and showed that the decomposition rate is sensitive to sample disposition. Amine evolution from both the (en) and propenediamine (pn) compounds was catalyzed by NH4C1 [1132,1133] or NH CN [1133,1285], addition of small amounts of these substances resulting in a substantial reduction of E. The influence of NH4C1 is ascribed [1132] to the dissociation products, since HC1 promoted the reaction but NH r and NH4I showed no such effect. 

Catalytic elfects on the thermal decomposition and burning under nitrogen of the nitrate were determined for ammonium dichromate, potassium dichromate, potassium chromate, barium chloride, sodium chloride and potassium nitrate. Chromium(VI) salts are most effective in decomposition, and the halides salts during burning of the nitrate [1]. The effect of chromium compounds soluble in the molten nitrate, all of which promote decomposition of the latter, was studied (especially using ammonium dichromate) in kinetic experiments [2],... 

Sodium chromate is produced as part of the process for obtaining Cr203, and it is probably the most important chromium compound. Although there are other oxides of chromium, Cr203 is very important because of its catalytic properties. One way to obtain this oxide is by the decomposition of ammonium dichromate,... 

Attempts to synthesize the chromium compounds in the absence of coordinating solvents were unsuccessful, and attempts to remove the base led to decomposition. Similar reactions with disodium tetracarbonyl ferrate gave the base-stabilized iron tetracarbonyl compounds shown in Eq. (52). Removal of the coordinated base gave the bridging structure shown (102). 

OSHA PEL CL 0.1 mg(Cr03)/m3 ACGIH TLV TWA 0.05 mg(Cr)/m3 Confirmed Human Carcinogen NIOSH REL (Chromium(VI)) TWA 25 ng(Cr(VI))/m3 CL 50 g/m3/15M SAFETY PROFILE A confirmed carcinogen. Poison. See also CHROMIUM COMPOUNDS and SULFATES. When heated to decomposition it emits toxic fumes of NH3, NOx, and SOx. 

SAFETY PROFILE A very flammable mixture. When heated to decomposition it emits acrid and irritating fumes. See CHROMIUM COMPOUNDS and ESTERS. 

OSHA PEL TWA 0.5 mg(Cr)/m3 ACGIH TLV TWA 0.5 mg(Cr)/m3 Not Classifiable as a Carcinogen SAFETY PROFILE Questionable carcinogen with experimental tumorigenic data. Moderately toxic by intravenous route. Human mutation data reported. See also CHROMIUM COMPOUNDS. When heated to decomposition it emits acrid smoke and irritating fumes. 

Human mutation data reported. When heated to decomposition it emits very toxic fumes of Pb. See also LEAD COMPOUNDS and CHROMIUM COMPOUNDS. 

SAFETY PROFILE Quesdonable carcinogen with experimental neoplastigenic and mmorigenic data. Human mutation data reported. A powerful oxidizer. Probably a severe eye, skin, and mucous membrane irritant. When heated to decomposition it emits toxic fumes of Pb, chromium trioxide, and Mo. See also LEAD COMPOUNDS, MOLYBDENUM COMPOUNDS, and CHROMIUM COMPOUNDS. 

SAFETY PROFILE Confirmed human carcinogen. When heated to decomposition it emits toxic fiimes of Na20. See also CHROMIUM COMPOUNDS and SODIUM CHROMATE. 

DIEXHYLENE GLYCOL METHYL ETHER ACETATE (629-38-9) Combustible liquid (flash point 180°F/98°C). Moisture may cause decomposition with formation of acetic acid. Reacts violently with strong oxidizers, permanganates, peroxides, ammonium persulfate, bromine dioxide, calcium chlorate, chlorosulfonic acid, oleum, sulfuric acid, nitric acid, perchloric acid, and other strong acids. Incompatible with acyl halides, aliphatic amines, alkalis, boranes, isocyanates, nitrates. May form shock-sensitive mixtures with silver, cobalt, chlorinated hydrocarbons, nitromethane, chromium compounds. Attacks some plastics, rubber, and coatings. Attacks copper, brass, zinc. 

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