Das Hydrogendiarsenit-Anion HAs2O5 3- Darstellung und Struktur von K3HAs2O5 • 6 H2O / The Hydrogendiarsenite Anion HAs2O53- Preparation and Structure of K3HAs2O5-6 H2O

Abstract

Abstract K3HAs2O5-6H2O 1 has been crystallised from aqueous solution and its crystal structure established by X-ray analysis. 1 contains isolated hydrogendiarsenite anions HAs2O5 3-, composed of two corner-sharing ψ -AsO3-tetrahedra. The anion displays the semi-eclipsed conformation in which the lone-pairs on the As atoms take up a syn-position with respect to an As-O bond on the opposite As atom. As a result the pyramidal coordination geometry of the As atoms is considerably distorted. The HAs2O5 3- anions in the crystal lattice are linked via O - H ··· O hydrogen bonds into infinite chains parallel to the b-axis, which are surrounded by water molecules of crystallisation