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Arsenic(V) acid is a weak acid and the salts are called arsenates, [5] the most common arsenic contamination of groundwater, and a problem that affects many people. Synthetic arsenates include Scheele's Green (cupric hydrogen arsenate, acidic copper arsenate), calcium arsenate, and lead hydrogen arsenate.
Arsenic is a common n-type dopant in semiconductor electronic devices. It is also a component of the III–V compound semiconductor gallium arsenide. Arsenic and its compounds, especially the trioxide, are used in the production of pesticides, treated wood products, herbicides, and insecticides. These applications are declining with the ...
In its standard state arsine is a colorless, denser-than-air gas that is slightly soluble in water (2% at 20 °C) [1] and in many organic solvents as well. [citation needed] Arsine itself is odorless, [5] but it oxidizes in air and this creates a slight garlic or fish-like scent when the compound is present above 0.5 ppm. [6]
Like all arsenic-containing compounds, arsonic acids are toxic and carcinogenic to humans. [1] [2] Arsonic acid refers to H 3 As O 3, the case where the substituent is a single hydrogen atom. The other arsonic acids can simply be viewed as hydrocarbyl derivatives of this base case. Arsenic acid results when the substituent is a hydroxyl group.
No appreciable hydrogen bonding is found in phosphine, arsine, stibine or bismuthine, and there is no appreciable tendency to dissociate like ammonia to MH + 4 and MH − 2 (M = P, As, Sb, Bi). The pnictogen hydrides become denser down the group and the M–H bond lengths increase, while the H–M–H bond angle decreases slightly.
Arsenic (III) binding sites usually use thiol groups of cysteine residues. The catalysis involves thiolates of Cys72, Cys174, and Cys224. In an SN2 reaction, the positive charge on the SAM sulfur atom pulls the bonding electron from the carbon of the methyl group, which interacts with the arsenic lone pair to form an As−C bond, leaving SAH. [31]
Similarly, realgar has arsenic–arsenic bonds, so the arsenic's oxidation state is +II. A corresponding compound for antimony is Sb 2 (C 6 H 5) 4, where the antimony's oxidation state is +II. Phosphorus has the +1 oxidation state in hypophosphorous acid and the +4 oxidation state in hypophosphoric acid.
Consequently, hydrogen bonds between or within solute molecules dissolved in water are almost always unfavorable relative to hydrogen bonds between water and the donors and acceptors for hydrogen bonds on those solutes. [44] Hydrogen bonds between water molecules have an average lifetime of 10 −11 seconds, or 10 picoseconds. [45]