Crystal Structure of Mercury(II) Hydroxide Nitrate. Refinement by Neutron Diffraction

Abstract

The crystal structure of mercury(II) hydroxide nitrate, Hg(OH)N03, has been reinvestigated by neutron diffraction to obtain information about the hydrogen-bond system. The crystals are monoclinic, space group P21/c, with a = 6.57 (1), 6=7.19 (1), c = 7.83(1) Å; β= 115° 40 (10); and Z = 4. All atoms were refined with anisotropic thermal parameters. The mercury and oxygen atoms build infinitive zigzag chains with [Hg(OH)]nn+ as the structural element where the oxygen atom is three-coordinate and the mercury-oxygen chain is a polymeric oxonium cation. The structural arrangement is such that these chains form quasi layers parallel to (100) with NO3 ions between them. The mercury atom has two covalent bonds with oxygen atoms inside the chain of lengths 2.079 (5) and 2.093 (5) Å, respectively, and five van der Waals contacts with nitrate oxygen atoms ranging from 2.678 (5) to 2.798 (5) Å. The hydrogen bond (O-H· -O) between oxonium and nitrate oxygen atoms is 2.772 (6) Å with an O-Hangle…O of 162.8 (6)° and an O-H bond length 0.974 (8) Å. © 1974, American Chemical Society. All rights reserved.