Oxalates metal

There have been many extensive and intensive studies of metal oxalate decompositions. Boldyrev et al. [1015] have suggested that these may be classified according to the three principle reactions 

Despite the differences in final products formed, these workers identify the initial step in the breakdown of all oxalates as C—C bond rupture in the anion (C204- 2 C02). This intermediate may be converted to the carbonate (through the carbonyl—carbonate intermediate) or to C02 (by electron transfer), viz. 

Reaction of COJ with H20 may yield formate and/or bicarbonate ions. 

The activation energy found for the decomposition of an individual oxalate ion in a KBr matrix (270 15 kJ mole-1) [292,294] is regarded as the energy requirement for C—C bond rupture. The generally lower values of E observed for many oxalates ( 165—175 kJ mole-1) are attributed to the facilitation of reaction at the reactant—product interface. 

These salts decompose [39] to the carbonates in the temperature intervals Li, 811-826 K Na, 737-814 K and K, 754-798 K (from DTA measurements, 5 K min-1). The reaction of lithium oxalate [98] (742— 765 K) obeyed the contracting volume equation [eqn. (7), n = 3] with E = 223 13 kJ mole-1. A marked increase in surface area during the initial stages of decomposition was later followed by extensive sintering. 

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Despite the volume of work concerned with metal-catalyzed decomposition of diazo compounds and carbenoid reactions 28>, relatively little work has been reported on the metal-catalyzed decomposition of sulphonyl azides. Some metal-aryl nitrene complexes have recently been isolated 29 31>. Nitro compounds have also been reduced to nitrene metal complexes with transition metal oxalates 32K... 

See Other CATALYTIC IMPURITY incidents, mercury compounds, metal OXALATES... 

See related metal oxalates See other platinum compounds... 

Oxalates are frequently obtained as hydrates, so the first reaction when a hydrated metal oxalate is heated is the loss of water. However, some metal oxalates decompose in a reaction that is quite different from that shown in Eq. (8.46). Several metal oxalates decompose according to the following equation ... 

The tendency for explosive decomposition of heavy metal oxalates is related to the value of the heat of decomposition. Individually entries are ... 

METAL NITROPHENOXIDES, METAL OXALATES METAL PYRUVATE NITROPHENYLHYDRAZONES metal OXOHALOGENATES (anion an oxo derivative of a halogen) metal oxometallates (anion an oxo derivative of a metal) metal oxonon-METALLATES (anion an oxo derivative of a non-metal) peroxoacid SALTS (anion a peroxo derivative of a metal or non-metal) There is a separate entry for... 

Other first-row transition metal oxalate complexes behave similarly." ... 

This class of compounds showing explosive instability deals with heavy metals bonded to elements other than nitrogen and contains the separately treated groups GOLD COMPOUNDS LEAD SALTS OF NITRO COMPOUNDS LITHIUM PERALKYLURANATES MERCURY COMPOUNDS METAL ACETYLIDES METAL FULMINATES METAL OXALATES PLATINUM COMPOUNDS PRECIOUS METAL DERIVATIVES SILVER COMPOUNDS... 

Precipitate the metal oxalate. Dissolve in acid and titrate the H2C204. 

Many different types of complex metal oxalates have been described, the best known being the trioxalato salts of the... 

Silver is incompatible with oxalic or tartaric acids, since the silver salts decompose on heating. Silver oxalate explodes at 140°C, and silver tartrate loses carbon dioxide. See other METAL OXALATES... 

See Other CATALYTIC IMPURITY INCIDENTS, MERCURY COMPOUNDS, METAL OXALATES... 

Vezes, M. Compt. rend., 1897, 125, 525 The salt decomposes violently at 240°C. See other PLATINUM COMPOUNDS See related METAL OXALATES... 

Weinland, R. et al., Z. Anorg. Chem., 1929, 178, 219 The salt, probably complex, decomposes at 100°C. See other METAL OXALATES... 

Metal cyanides(and cyano complexes), 216 Metal derivatives of organofluorine compounds, 217 IV-Metal derivatives, 218 Metal dusts, 220 Metal fires, 222 Metal fulminates, 222 Metal halides, 222 Metal—halocarbon incidents, 225 Metal halogenates, 226 Metal hydrazides, 226 Metal hydrides, 226 Metal hypochlorites, 228 Metallurgical sample preparation, 228 Metal nitrates, 229 Metal nitrites, 231 Metal nitrophenoxides, 232 Metal non-metallides, 232 Metal oxalates, 233 Metal oxides, 234 Metal oxohalogenates, 236 Metal oxometallates, 236 Metal oxonon-metallates, 237 Metal perchlorates, 238 Metal peroxides, 239 Metal peroxomolybdates, 240 Metal phosphinates, 240 Metal phosphorus trisulfides, 240 Metal picramates, 241 Metal pnictides, 241 Metal polyhalohalogenates, 241 Metal pyruvate nitrophenylhydrazones, 241 Metals, 242 Metal salicylates, 243 Metal salts, 243 Metal sulfates, 244 Metal sulfides, 244 Metal thiocyanates, 246 Metathesis reactions, 246 Microwave oven heating, 246 Mild steel, 247 Milk powder, 248... 

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