Diphenylchlorarsine
Diphenylchloroarsine (DA) is the organoarsenic compound with the formula (C6H5)2AsCl. It is a low-melting solid. It is highly toxic and was once used in chemical warfare. It is also an intermediate in the preparation of other organoarsenic compounds. The molecule consists of a pyramidal As(III) center attached to two phenyl rings and one chloride.
Preparation and structure
It was first produced in 1878 by Michaelis and La Coste. It is prepared by the reduction of diphenylarsonic acid with sulfur dioxide. An idealized equation is shown:
The structure consists of pyramidal As centre. The As-Cl distance is 2.26 A and the Cl-As-C and C-As-C angles are 96 and 105°, respectively.
Uses
It is a useful reagent for the preparation of other diphenylarsenic compounds, e.g. by reactions with Grignard reagents:
Safety
Diphenylchlorarsine is known to cause sneezing, coughing, headache, salivation, and vomiting. China and Japan are negotiating remediation of stocks of a variety of organoarsenic weapons dumped in northeastern China after Japan's numerous invasions of China, including chlorodiphenylarsine.
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