Arsenic vapor pressure

Not all molecules striking a surface necessarily condense, and Z in Eq. VII-2 gives an upper limit to the rate of condensation and hence to the rate of evaporation. Alternatively, actual measurement of the evaporation rate gives, through Eq. VII-2, an effective vapor pressure Pe that may be less than the actual vapor pressure P. The ratio Pe/P is called the vaporization coefficient a. As a perhaps extreme example, a is only 8.3 X 10" for (111) surfaces of arsenic [11]. 

Arsenic(V) fluoride is introduced into the Pyrex bulb to a pressure of 250 mm. The stopcock is closed and the bulb immersed in Dry Ice or liquid nitrogen. [Antimony(V) fluoride has only a few millimeters of vapor pressure at 25°C., but it can easily be distilled into the bulb and the quantity determined by... 

As203 (liq.). The above vapor pressure data yield a surprisingly large value for the heat of fusion of solid arsenic trioxide. 

Baxter, G.P., Bezzenberger, F.K., Wilson, C.H. (1920) The vapor pressures of certain substances Chloropicrin, cyanogen bromide, methyl-dichloro-arsine, phenyl-dichloro-arsine, diphenyl-chloro-arsine and arsenic trichloride. J. Am. Chem. Soc. 42, 1386-1393. 

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). 

CCA chromated copper arsenate h relative vapor pressure... 

Direct reaction is feasible for the IVA-VA compounds. This is surprising, since a low vapor pressure element, such as silicon, would be expected to passivate on exposure to phosphorus or arsenic. The valve metal analogy to electrochemical reactions may be invoked here fresh silicon probably diffuses rapidly through the compound, providing a continuous supply of reactant. A cold zone with a temperature of less than 500°C supplies phosphorus to the silicon, kept slightly near the 1 1 SiP melting point of 1166°Ck... 

As a metalloid, arsenic has both metallic and nonmetallic properties. Elemental arsenic exists at room temperature as metallic or gray arsenic and yellow arsenic. Gray arsenic represents the common stable form. Its density is 5.73 gcm , melting point 814 °C at 36.5 bar pressure, and vapor pressure 1 bar at 604°C (sublimating). Metallic arsenic is not soluble in common solvents. Yellow arsenic has a density of... 

BEH/ROS] Behrens, R. G., Rosenblatt, G. M., Vapor pressure and thermodynamics of octahedral arsenic trioxide (arsenolite), J. Chem. Thermodyn.,4, 912), 175-190. Cited on pages 249,404. 

No peaks could be detected for samples with arsenic concentrations below 100 ppm (Thurow et al., 1998), since the concentration of the analyzed compound in the head-space is to low due to low vapor pressure. Thus headspace analysis is suitable for rapid screening procedures but can not be used for trace analysis. The reproducibility of the headspace results was about 2%. 

Requirements for Respiratory Protection for Inorganic Arsenic Particulate Except for Those With Significant Vapor Pressure... 

Pure arsenic(iii) bromide could be prepared by the treatment of AS4O6 152 with HBr in high yield (81%). However, the yield is reduced if the evacuation is prolonged after removal of the extraction solvent (hexane), since the vapor pressure of AsBrs is significant, although AsBts is a colorless crystalline solid that melts at 32 °C (Scheme 50) <2002IS(33)203>. 

Arsenic (CAS 7440-38-2) irritating to eyes and skin hyperplgmenta-tion, hyperkeratoses, and skin cancers have been dexribed. A general cellular poison. May cause bone marrow suppression, peripheral neuropathy, and gastrointestinal, liver, and cardiac injury. Some arsenic compounds have adverse effects on fetal development in test animals. Exposure linked to skin, respiratory tract, and liver cancer in workers (IARC 1). See also p 115. 0.01 mg/m (as As) A1 OSHACA NIOSH CA 5 mg/m (as As) Elemental forms vary In appearance. Crystals are gray. Amorphous fomes may be yellow or black. Vapor pressure is very low—about 1 mm Hg at 372°C (701°F). 

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