Metal hydrides arsine

The synthesis of alkali metal organophosphides and arsenides is usually most conveniently achieved by the direct metalation of a primary or secondary phosphine/arsine with a strong deprotonating agent such as an alkyllithium or an alkali metal hydride ... 

Today, metal hydrides can be synthesised in purchasable equipment. Principally a solution which contains AsCl3 or SbCl3 is pre-reduced, with for example KI and ascorbic acid, and then reduced with sodium borohydride to arsine or stibine. This is done in a closed system and the method is simple (Fig. 13). The determination of As via arsine in iron ores is now available as draft proposal ISO/TCI 02. The method described for the concentration range of 0.0001—0.05 mass% is as follows. 

Ignition or explosive reaction with metals (e.g., aluminum, antimony powder, bismuth powder, brass, calcium powder, copper, germanium, iron, manganese, potassium, tin, vanadium powder). Reaction with some metals requires moist CI2 or heat. Ignites with diethyl zinc (on contact), polyisobutylene (at 130°), metal acetylides, metal carbides, metal hydrides (e.g., potassium hydride, sodium hydride, copper hydride), metal phosphides (e.g., copper(II) phosphide), methane + oxygen, hydrazine, hydroxylamine, calcium nitride, nonmetals (e.g., boron, active carbon, silicon, phosphoms), nonmetal hydrides (e.g., arsine, phosphine, silane), steel (above 200° or as low as 50° when impurities are present), sulfides (e.g., arsenic disulfide, boron trisulfide, mercuric sulfide), trialkyl boranes. 

Metals in a finely divided state bum spontaneously in chlorine. Solid metals (nonpow-dered form) bum spontaneously at elevated temperatures. Metal carbides react with chlorine with incandescence. Metal hydrides bum spontaneously in chlorine. Diborane explodes with chlorine at ordinary temperature silane, phosphine, arsine, or stibine produce a flame. The latter compounds react explosively with chlorine at elevated temperatures. Metal sulfides, silicides, nitrides, phosphides, and oxides bum in chlorine. Phosphorus undergoes a highly exothermic reaction with chlorine. White phosphorus explodes with liquid chlorine white phosphorus and finely divided red phosphorus bum spontaneously in chlorine gas with a pale green light (NFPA 1997). 

Covalent volatile hydrides, such as arsine, silane, or germane, are highly toxic. Ionic alkali metal hydrides are corrosive to skin, as they form caustic alkalies readily with moisture. 

Reactivity and Incompatibility Ozone is a powerful oxidant and can react explosively with readily oxidizable substances and reducing agents. Explosions can occur when ozone is exposed to bromine, hydrogen bromide, hydrogen iodide, nitrogen oxides, lithium aluminum hydride, metal hydrides, hydrazine, alkyl metals, stilbene, ammonia, arsine, and phosphine. Ozone reacts with alkenes and other unsaturated organic compounds to form ozonides, many of which are highly unstable and explosive. Ozone combines with many aromatic compounds and ethers to form shock-sensitive and explosive products. 

The combination of arsenic with dry nascent hydrogen was observed by Vournazos,14 who obtained a mixture of hydrogen and arsine by heating rapidly to 400° C. in a round-bottomed flask a mixture of three parts of powdered arsenic with eight parts of dry sodium formate. The addition of sodium hydroxide or lime to the mixture prevents the formation of sodium oxalate and hence of carbon monoxide. Arsenious oxide, sodium arsenite or arsenic acid may be used in place of arsenic, but the yields are small. The gas is also formed if arsenic vapour is passed over heated sodium formate. Also, if the sulphide or phosphide of arsenic is heated with the formate, hydrides of both components of the arsenic compound are formed but with metallic arsenides the hydride of the non-volatile component is not formed. 

The hydrides phosphine PH3, arsine ASH3 and stibine SbH3 can be prepared by hydrolysis of metal phosphates, or by reduction of molecular compounds like PC13. They are very toxic gases, with decreasing thermal stability P > As > Sb. Unlike ammonia they are not basic in water. The hydrazine... 

A very substantial number of these are known (examples are given in Table 18) as with the halo-arsines (p. 576) and -stibines (p. 577) the metal oxidation states represented are II, III and IV with a preponderance of the trivalent state the early-reported Os(PPh3)3X (X = Cl, Br) complexes are now known to be hydrides, Os(PPh3 )3 HXfCO).40 ... 

Mnltinnclear Re hydrides, in particnlar CO/phosphine complexes, with the hydride bridging two or three metals and componnds with H atoms bridging Re and other metals, for example, obtained from the reactions of Re polyhydrides with metal salts, have been reported. The coordination chemistry of hydrido/phosphine complexes has been extended, in a nnmber of cases, to related phosphite, phosphonite, or arsine complexes. ... 

Reduction by Hydrazine. This was a very successful method for preparing the palladium (0) and platinum (0) derivatives with tertiary phosphines, phosphites, and arsines (4, 129, 130, 133). Also, the tetra-isocyanidenickel(O) compounds can be obtained at high yield in this way (132). In the case of platinum this reduction can give place either to zero valent derivatives (130) or to platinum (II) hydrides (49), according to the reaction conditions, the nature of the ligands, and the halogen atoms bound to the metal. This reduction is a very complicated reaction (186) in any case. 

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