Arsenic chemistry

1 University of Kentucky Center for Applied Energy Research 2 Department of Science and Mathematics, Cedarville University 

Arsenic is a group 15 element on the periodic table along with nitrogen, phosphorus, antimony, and bismuth. The atomic mass of arsenic is 74.921 60 atomic mass units (amu) and its atomic number (Z) 

Arsenic Edited by Kevin R. Henke 2009 John Wiley Sons, Ltd. ISBN 978-0-470-02758-5 

The electrons in an uncharged arsenic atom (As0) are located in the s subshell of the first principal quantum number (n = 1), the s and p subshells of principal quantum numbers 2-4 (n = 2-4), and the d subshell of the third principal quantum number (n = 3). Specifically, the As0 electron configuration may be written as  

The s subshells have one orbital, the p subshells have three, and the d subshell has five. Each orbital may contain up to two electrons. For example, the 2p subshell has a total of six electrons, where each of the three 2p orbitals contains two electrons (Faure, 1998), 63-71. 

---

The Meyer Reaction in arsenic chemistry bears some analogy to the Arbusov Reaction in phosphorus chemistry. 

As part of an impressive series of papers on arsenic chemistry, Ioan-nou and colleagues have developed methods for making arsenic analogues of natural phospholipids. They first made racemic 2,3-dihydroxy-propylarsonic acid, the nonisosteric analogue of glycerol 3-phosphate... 

The As—N bond is labile and this has been widely exploited in synthetic arsenic chemistry. Some idea of the versatility168 can be seen from Schemes 1 and 2. Refluxing secondary amines with tris(dimethylamino)arsine effects transamination (equation 6). These tris(dialkyl-amino)arsines undergo the general reactions in Scheme 1, enabling ready access to a wide variety of compounds, many of them finding use as ligands in transition metal complexes (see Chapter 14 of this work). 

The synthetic routes developed in arsenic chemistry usually also apply to antimony, but they have not been as fully investigated. A good outline of organoantimony chemistry has been... 

McNeill, L.S., Chen, H. and Edwards, M. (2002) Aspects of arsenic chemistry in relation to occurrence, health and treatment, in Environmental Chemistry of Arsenic (ed. W.T. Frankenberger Jr.), Marcel Dekker, New York, pp. 141-53. 

Arsenic chemistry of the solar system 3.4.1 Arsenic in the Sun, Moon, and planets... 

No rock samples have been collected from Mercury and Venus, and the arsenic chemistry of their crusts is unknown. Like the Moon, the crustal rocks on Mercury, Venus, and Mars are primarily basalts and other mafic rocks. If the trace element chemistry of their basalts is similar to lunar specimens, they should contain <1 mg kg-1 of arsenic. 

Table 3.3 Estimated arsenic chemistry of the bulk Earth and its internal layers.

Any relationships between salinity and arsenic chemistry in estuary waters often vary with location and climate. In some areas, periodic upwelling of high-arsenic and saline bottom waters locally dominates the arsenic chemistry of estuaries (e.g. the Taiwan Strait (Xiankun, Jing and Xinian, 1994), 332). In other situations, wet season flooding of highly arsenic-contaminated river waters increases the arsenic contents and lowers the salinity of estuaries. In contrast, fairly pristine river waters may dilute both estuary salinity and arsenic concentrations during flooding. 

The arsenic chemistry of the Krka estuary, Croatia, is very pristine that is, essentially unaffected by arsenic pollution from humans. Total dissolved arsenic concentrations in the estuary waters vary from 0.13 to 1.8 pgL-1 (Table 3.7 (Smedley and Kinniburgh, 2002), 525). The range of concentrations can be readily explained by low-arsenic (0.13 pg E1) river water simply diluting 1.8 pgL-1-arsenic seawater in various proportions (Smedley and Kinniburgh, 2002), (Seyler and Martin, 1991), 525. In this estuary, arsenic (in particular As(V)) behaves conservatively that is, the element is relatively unreactive in at least the short... 

Arsenic in precipitation from unpolluted ocean air averages about 0.019 pg L 1 (Hering and Kneebone, 2002), 157 and terrestrial rainwater concentrations (at least over the USA) also have similar averages of around 0.013-0.032 pgL-1 ((Smedley and Kinniburgh, 2002), 522 Table 3.17). As the precipitation infiltrates into the subsurface, its chemistry changes as it reacts with sediments, soils, and rocks. Therefore, the arsenic chemistry of the groundwater of an area may be very different than its precipitation chemistry. 

---