Arsenic metallic

Physical properties of a-crystaUine metallic arsenic are given in Table 1. The properties of P-arsenic are not completely defined. The density of P-arsenic is 4700 kg/m it transforms from the amorphous to the crystalline form at 280 °C and the electrical resistivity is reported to be 107 H-cm. 

Metafile arsenic can be obtained by the direct smelting of the minerals arsenopyrite or loeUingite. The arsenic vapor is sublimed when these minerals are heated to about 650—700°C in the absence of air. The metal can also be prepared commercially by the reduction of arsenic trioxide with charcoal. The oxide and charcoal are mixed and placed into a horizontal steel retort jacketed with fire-brick which is then gas-fired. The reduced arsenic vapor is collected in a water-cooled condenser (5). In a process used by Bofiden Aktiebolag (6), the steel retort, heated to 700—800°C in an electric furnace, is equipped with a demountable air-cooled condenser. The off-gases are cleaned in a sembber system. The yield of metallic arsenic from the reduction of arsenic trioxide with carbon and carbon monoxide has been studied (7) and a process has been patented describing the gaseous reduction of arsenic trioxide to metal (8). 

The demand for metallic arsenic is limited and thus arsenic is usually marketed in the form of the trioxide, referred to as white arsenic, arsenious oxide, arsenious acid anhydride, and also by the generally accepted misnomer arsenic. 

The demand for arsenic metal is limited. The 1990 U.S. requirement for metallic arsenic was supphed by the People s Repubhc of China. Arsenic was formerly supphed domestically (1974—1986) by ASARCO Inc., which dismantled its operation because of economic and environmental pressures, and by imports from Bohden Metah, Sweden, which suspended production in late 1987 because of the low price offered by China. 

The toxicity of arsenic ranges from very low to extremely high depending on the chemical state. Metallic arsenic and arsenious sulfide [1303-33-9] AS2S2, have low toxicity. Arsine is extremely toxic. The toxicity of other organic and inorganic arsenic compounds varies (28). 

Napfehen, n. cup little bowl or basin blank (for blasting caps) cupule. -kobalt, m. flaky metallic arsenic. 

Hazardous waste burning incinerators, cement kilns, and LWAKs do not follow a tiered approach to regulate the release of toxic metals into the atmosphere. The MACT rule finalized numerical emission standards for three categories of metals mercury, low-volatile metals (arsenic, beryllium, and chromium), and semivolatile metals (lead and cadmium). Units must meet emission standards for the amount of metals emitted. For example, a new cement kiln must meet an emission limit of 120pg/m3 of mercury, 54pg/m3 of low-volatile metals, and 180 pg/m3 of semivolatile metals. 

Low-volatile metals (arsenic + beryllium + chromium) 92 pg/dscm 2.1 E-5 lb/MMBtu and 56 flg/dscm 9.5 E-5 lb/MMBtu and llOpg/dscm 380 pg/dscm 1.26 E-4 lb/MMBtu or 370pg/dscm depending on Btu content of hazardous TCI standard as surrogate... 

Metal-Arsenic Bond Lengths, Torsion Angles between the Metal and Arsenic Coordination Planes, and Sums of the Angles at Arsenic for Three-Coordinate Gallium and Indium Arsenides... 

The reaction wtih As4, generated by vaporization of metallic arsenic into cold toluene, has so far been reported only for l.101 Two principal products (79%) were formed in 1 3 ratio the bicyclobutane 72 and the remarkable compound 73 (Scheme 19). The structure of the latter was established by X-ray crystallography. It appears to be an intermediate on the reaction pathway, since long heating at 95°C converted it completely to 72. 

Relatively soon after ancient humans recognized the metals and their special properties, they also discovered ways to make alloys. Some alloys were produced in antiquity directly, by the smelting of ores that include two metals in their composition or mixtures of ores of different metals. Arsenical copper, bronze, and brass, for example, three alloys of copper... 

Again, the waste treatment scenario with incineration has by far to the highest score for human toxicity. The scores for the other scenarios are more or less the same. The incineration of EoL PVC will lead to toxic emissions of metals (arsenic, lead, chromium, see Table 5) causing human health effects. However, the most important contribution to the human health effect is caused by the emission of mercury in the upchain processes of the production of mercury and sodium hydroxide. Sodium hydroxide is an auxiliary material in the waste incineration process. Mercury... 

Taylor, D., B.G. Maddock, and G. Mance. 1985. The acute toxicity of nine grey list metals (arsenic, boron, chromium, copper, lead, nickel, tin, vanadium and zinc) to two marine fish species dab (Limanda limanda) and grey mullet (Chelon labrosus). Aquat. Toxicol. 7 135-144. 

We have studied the toxicokinetics of heavy metals (arsenic, lead, manganese and copper), as well as of organophosphorus and clorinated pesticides. It has been shown that they are all characterized by different... 

KEYWORDS ochre-precipitates, mine water, metals, arsenic, concentration factors. 

Alkali Metal-Phosphorus and Alkali Metal-Arsenic Clusters I 403... 

Metal-Phosphorus and Alkali Metal—Arsenic Clusters I 409... 

Hermann, E., DulUes, F., Griebel, I., and KieBig, G., 2001, Filter material and process for the removal of heavy metals, arsenic, uranium, and radium from contaminated waters, Patents Pending DE 101 16 951, DE 101 16 953 (2001). 

Arsenic is a metalloid, yet it is still classified as a heavy metal. Arsenic compounds have also been known since ancient times, but was described for... 

Trace metals (arsenic, cadmium, chromium, copper, nickel, lead, mercury, zinc) Industrial and municipal wastewaters runoff from urban areas and landfill erosion of contaminated soils and sediments atmospheric deposition Toxic effects including birth defects, reproductive failure, cancer, and systemic poisoning. 

Forget, J., Pavilion, J.F., Menasria, M.R., and Bocquene, G. Motality and LC50 values for several stages of the marine copepod Tigriopus brevicornis (Muller) exposed to the metals arsenic and cadmium and the pesticides atrazine, carbofuran, dichlorvos, and malathion, Ecotoxlcol. Environ. Saf., 40(3) 239-244, 1998. 

Some metals, arsenic and mercury for example, may be volatilized by methylation due to activity of anaerobic microorganisms. Arsenic can be methylated by methanogenic Archaea and fungi to volatile toxic dimethylarsine and trimethylarsine or can be converted to less toxic nonvolatile methanearsonic and dimethylarsinic acids by algae [42]. 

Toxic pollutants (p,g/L) Toxic metals Arsenic Cadmium Chromium 3 3 10,000-26,000 12,000 16,000... 

Synonyms and Compounds Grey arsenic metallic arsenic arsenic trichloride arsenic trioxide arsenic salts... 

Physical Form. Metallic arsenic is a steel gray brittle metal arsenic trichloride is an oily liquid arsenic trioxide is a crystalline solid... 

Metals are essential for humans and indeed for all life. We began using metals to build and shape our society over 4000 years ago. The Greeks and Romans were some of the first to document both the toxic and potential healing effects of metals. Arsenic was well known both as a poison and treatment for disease. 

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