Anhydrous Mercurous Chlorate, Hg 2 (ClO 3 ) 2

Colourless single crystals of the anhydrous mercurous chlorate were grown from a solution of mercuric oxide (HgO) in chloric acid (HClO 3 ) in the presence of elemental mercury. The crystal structure (monoclinic, P2 1 /n, Z = 4, a = 816.59(12), b = 641.02(5), c = 1290.3(2) pm, β = 97.506(12)°, R(all) = 0.0317) contains trans‐O 2 ClO‐Hg‐Hg‐OClO 2 molecules with a Hg‐Hg distance of 251.03(4) pm, Hg‐O (bond) distances of 218 and 224 pm and Hg‐Hg‐O angles of 177 and 165°, respectively.