Über Arsen-haltige Heterocyclen. IV. Kristallstruktur von 2,6-Dimethyl-4,4-diphenyl-1,4-oxarsenaniumnitrat

On Heterocyclic Systems Containing Arsenic. IV. Crystal Structure of 2,6-Dimethyl-4,4-diphenyl-1,4-oxarsenanium Nitrate The crystal structure of the title compound 2 has been determined from single crystal X-ray data and refined to a conventional R of 0.037. The coordination of the As atom is tetrahedral with a mean As? C distance of 191 pm. The six-membered heterocycle has chair conformation with a transannular 1,4-As…O distance of 310 pm. The conformation of the cation of 2 is quantitatively barely different from the analogous bromide compound and can be accepted as standard conformation for this type of cation. In the crystal structure the cations are connected partly by tridental bridgeing nitrate anions and mostly by VAN DER WAALS contacts.