Arsine Chemical properties

The unusual fluorocarbon ligand geometry reported last year for [(AsMe2-CF2CFHAsMe2)Cr(CO)4] and related compounds are incorrect. The X-ray data and chemical properties of the compounds are better interpreted in terms of a disordered arrangement of molecules with normal geometries and dimensions. The ditertiary arsine chelates (53) have been synthesized by the... 

Chemical Properties.—Arsine in the pure state is fairly stable, but in accordance with its endothermic nature it undergoes gradual decomposition into arsenic and hydrogen even when kept in a sealed tube in the dark. Under the latter conditions black particles of arsenic... 

Four arsenic species common in natural samples are arsenate, arsenite, methanearsonic acid (MMAA) and dimethylarsinic acid (DMAA). These species possess different chemical properties which affect the mobility of arsenic in natural systems. For example, methanobacteriurn form trimethyl arsine from DMAA faster than fromMMAAor arsenate 3) and arsenate and MMAA are more strongly adsorbed than DMAA on alluvial soils ( ). Transformation between the different oxidation states and species of arsenic may occur as a result of chemical or biochemical reactions (J, 2, 7, 9). Inorganic chemical... 

These arsines differ from those of the aliphatic series which have just been described, by their physical and chemical properties, and by their method of employment, as well as by their biological action. They are solids or liquids with high boiling points, have very low vapour tensions, are quite resistant to heating and are only oxidised by atmospheric oxygen with difficulty. 

The term blister agents includes a wide range of compounds with diverse physical and chemical properties and chemical structures. They may be broadly grouped under a few general types, namely, the sulfur mustards, nitrogen mustards and organochloro-arsines. There are also some substances that do not fall nnder the above categories. 

Elemental arsenic is a gray, crystalline material characterized by atomic number 33, atomic weight of 74.92, density of 5.727, melting point of 817°C, sublimation at 613°C, and chemical properties similar to those of phosphorus. Arsenic has four valence states —3, 0, -1-3, and -1-5. Arsines and methylarsines, which are characteristic of arsenic in the —3 oxidation state, are generally unstable in air. Elemental arsenic, As° is formed by the reduction of arsenic oxides. Arsenic trioxide (As+ ) is a product of smelting operations and is the material used in synthesizing most arsenicals. It is oxidized catalytically or by bacteria... 

TABLE 15.1 Table Showing Physical and Chemical Properties of Arsine... 

Substances with high vapor pressure evaporate rapidly. Those with low vapor pressure evaporate slowly. The impact of vapor pressure on the rate of evaporation makes vapor pressure a very important property in considering the tactical use and duration of effectiveness of chemical agents. A potential chemical agent is valuable for employment when it has a reasonable vapor pressure. One with exceptionally high vapor pressure is of limited use. It vaporizes and dissipates too quickly. Examples are arsine and carbon monoxide. On the other hand, mechanical or thermal means may effectively aerosolize and disseminate solid and liquid agents of very low vapor pressure. Vapor pressure and volatility are related. Translated into volatility, vapor pressure is most understandable and useful. 

Barium Arsenide, Ba3As2.—By passing arsine over barium oxide at red heat Soubeiran 4 obtained a mixture of arsenide and arsenite. Lebeau 6 prepared the pure arsenide by reduction of barium arsenate with carbon in an electric furnace. Barium arsenide is very similar in properties to the arsenides of calcium and strontium it is slightly darker in colour, more readily fusible and more reactive chemically. Its density at 15° C. is 4-1. It burns spontaneously in fluorine, chlorine or bromine vapour. In oxygen it burns at about 300° C. and in sulphur vapour at dull red heat. 

Lewisite [dichloro(2-chlorovinyl)arsine] is an organic arsenical known for its vesicant properties (Rosenblatt et al., 1975). It has a molecular weight of 207.32, vapor pressure of 0.58 mm HG at 25°C, a liquid density of 1,89 g/cm at 25°C, freezing point of -18°C, boiling point of 190°C, and is negligibly soluble in water (DA, 1974). The chemical structure of lewisite is shown below. Lewisite may occur as a trans-isomer and as a cis-isomer. In aqueous solutions, the cis-isomer undergoes photoconversion to the trans-isomer (Clark, 1989). hi the presence of moisture, lewisite is rapidly converted to the more stable but highly toxic lewisite oxide (2-chlorovinylarsenous acid) (Cameron et al., 1946). 

Lewisite [L or L-1 dichloro(2-chlorovinyl) arsine] is an arsenical vesicant developed early in the 20th century. Lewisite occurs as cis- and tranx-isomers the typical ratio being 10 90. Several impiuities including 6w(2-chlorovinyl) chloroarsine (L-2) and tnY(2-chlorovinyl)arsine (L-3) are typically present. The chemical and physical properties of the cis- and tranj-isomers are similar. 

Stibine is an irritant to the lung. Other toxic symptoms from inhaling this gas are headache, weakness, nausea, and abdominal pain. There is no report on its carcinogenicity in animals or humans. Because of its similarity to arsine in chemical and toxicological properties, stibine is expected to exhibit carcinogenic action. 

Lewisite is composed of cis- and trans-isomers in the ratio of 10 90 and several impurities including bis(2-chlorovinyl)chloroarsine (L-2) and tris(2-chlorovinyl) arsine (L-3) (Rosenblatt et al., 1975). The chemical and physical properhes of the cis- and trans-isomers are similar. Tlie nomenclature and chemical and physical properties of L-1, L-2, and L-3 are presented in Tables 8.5... 

---