Arsenic compounds, Table

Arsenic is a major constituent of at least 245 mineral species, of which arsenopyrite is the most common (NAS 1977). In general, background concentrations of arsenic are 0.2 to 15 mg/kg in the lithosphere, 0.005 to 0.1 pg/m3 in air, <10 pg/L in water, and <15 mg/kg in soil (NRCC 1978 ATSDR 1992). The commercial use and production of arsenic compounds have raised local concentrations in the environment far above the natural background concentrations (Table 28.1). 

Table 28.3 Lethal and Sublethal Effects of Various Arsenic Compounds on Selected Species of...

In chemical combination, arsenic can exist in oxidation state III or V and can have a coordination number of 3, 4, 5, or 6. In marine samples, arsenic is mainly found in the V oxidation state, although, usually as a consequence of biological factors, arsenic (III) compounds can also occur and may at times be predominant. The properties and analysis of the various arsenic-containing compounds of significance in marine arsenic research are briefly discussed, and information is provided on their synthesis. For ease of reference, the arsenic compounds frequently mentioned by name (or abbreviation/acronym) are listed in Table IV together with their structure numbers. 

Arsenobetaine was the first arsenic compound identified in a marine animal when it was isolated in 1977 in a crystalline form from the tail muscle of the western rock lobster Panulirus cygnus (48). The large body of work that followed established that arsenobetaine was by far the predominant form of arsenic in marine animals (Table VI). It occurs at all trophic levels, although there is a tendency for it to be present at higher concentrations (or at least constitute the greater percentage... 

The thirty-third member of the Periodic Table has a sinister reputation. Since its isolation in the Middle Ages the main use of arsenic compounds has been the termination of lifeforms. Its use for homicide was widened to include inter alia herbicide, fungicide and bactericide (see Section 28.7). Various arsenic compounds have been used from ancient times as pigments, e.g, lemon-yellow orpiment, As2S3, and red realgar, As4S4. 

Native Arsenic—Compounds of Arsenic—Tables of Minerals Containing Arsenic —The Ubiquity of Arsenic. 

Table 2.8 Solubility of some arsenic compounds in water at atmospheric pressure.

Table 2.9 Equilibrium constants (including some solubility product constants, Ksp values, from Lide (2007), Krause and Ettel (1988), Bothe and Brown (1999), Davis (2000), Nordstrom and Archer (2003), Langmuir, Mahoney and Rowson (2006), Lee and Nriagu (2007), Zhu et al. (2005), and Zhu et al. (2006)) for reactions with various arsenic compounds in water at 1 bar pressure. pK = -logw K. ... 

Table 4.1 Examples of arsenic compounds of environmental and biological interest. Inorganic arsenicals Organic arsenicals...

The inorganic compounds in Table 1 include arsenic compounds, cadmium sa1ts lead chloride, lead nitrate, and mercury salts. These are highly poisonous compounds as well as being suspected teratogens, and they need to be handled with extra care. Fortunately, most of these substances are used only in dilute solution and usually in semi-micro quantities. Solutions of arsenic, cadmium, lead, and mercury salts are typically used in connection with Qualitative Analysis procedures, and the amounts used are often no more than a few drops. Hand washing at the end of the laboratory period is especially important after working with solutions such as these. 

The reaction product of arsenic trichloride (see Table 1) with 3,4-dimercaptotoluene, 2-chloro-5-methyl-l,3,2-benzodithiarsole, still contains an active chlorine atom, rendering its determination by GC/MS difficult. The derivatization reaction can also be carried out with 2-chlorovinylarsenic oxide (lewisite oxide, CAS 3088-37-7), which is one of the degradation products of lewisite 1. Thus, the highly reactive arsenous compounds can be detected as less reactive derivatives amenable to GC/MS. 

While several metals show at least some evidence of carcinogenicity (see Table 21.1), five metals are classified by the International Agency for Research on Cancer (IARC) as carcinogenic to humans. Arsenic and arsenic compounds, beryllium and... 

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