The channel structure of the mercury(II) selenite(IV) oxide hydrate HgSeO3.HgO.1/6H2O.

The main building units of the title compound, dimercury(II) selenite(IV) oxide hydrate, are strongly distorted [Hg1O(6)] and [Hg2O(7)] polyhedra, and a pyramidal Se(IV)O(3) group. Slightly corrugated hexagonal rings made up of six [Hg1O(6)] octahedra spread parallel to the ab plane and are connected via [Hg2O(7)] polyhedra parallel and perpendicular to this direction, which results in a three-dimensional arrangement with channels propagating parallel to the c axis. The Se(IV)O(3) groups are situated below and above the rings and bridge both types of Hg atoms. The non-bonding orbitals are stereochemically active and protrude into the channels of the three-dimensional network. Additional water molecules are located at the centres of the channels and show weak interactions with the Se(IV) lone pairs and the O atoms of the Se(IV)O(3) groups.