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Arsenic makes arsenic acid with concentrated nitric acid, arsenous acid with dilute nitric acid, and arsenic trioxide with concentrated sulfuric acid; however, it does not react with water, alkalis, or non-oxidising acids. [32]
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]
Arsenic trioxide powder.. Compounds of arsenic resemble in some respects those of phosphorus which occupies the same group (column) of the periodic table.The most common oxidation states for arsenic are: −3 in the arsenides, which are alloy-like intermetallic compounds, +3 in the arsenites, and +5 in the arsenates and most organoarsenic compounds.
As reported in 1775, Carl Scheele reduced arsenic(III) oxide with zinc in the presence of acid. [11] This reaction is a prelude to the Marsh test. Alternatively, sources of As 3− react with protonic reagents to also produce this gas. Zinc arsenide and sodium arsenide are suitable precursors: [12]
Other reactions of main group compounds with yellow arsenic have been shown to involve units of arsenic with more than four atoms. In reaction with the silylene compound [PhC(N t Bu) 2 SiN(SiMe 3 ) 2 ], an aggregation of As 4 was observed to form a cage compound of ten arsenic atoms, including a seven-membered arsenic ring at its center.
Arsenic acid or arsoric acid is the chemical compound with the formula H 3 AsO 4. More descriptively written as AsO(OH) 3, this colorless acid is the arsenic analogue of phosphoric acid. Arsenate and phosphate salts behave very similarly. Arsenic acid as such has not been isolated, but is only found in solution, where it is largely ionized.
Arsenic trioxide is an inorganic compound with the formula As 2 O 3. [5] As an industrial chemical, ... This reaction is used in the Marsh test. Structure
It can also be prepared by chlorination of arsenic at 80–85 °C, but this method requires elemental arsenic. [4] 2 As + 3 Cl 2 → 2 AsCl 3. Arsenic trichloride can be prepared by the reaction of arsenic oxide and sulfur monochloride. This method requires simple apparatus and proceeds efficiently: [8] 2 As 2 O 3 + 6 S 2 Cl 2 → 4 AsCl 3 + 3 ...