Disorder of (NH4)(3)H(SO4)(2) in the high-temperature phase I

作者：Sohn Yoo Jung^*; Sparta Karine M; Meven Martin; Heger Gernot

来源：Acta Crystallographica Section B-Structural Science, 2011, 67(2): 116-121.

DOI：10.1107/S0108768111007269

• disorder
• neutron diffraction
• high-temperature phase
• hydrogen bonding
• split-atom model

The highly disordered crystal structure of triammonium hydrogen disulfate, (NH4)(3)H(SO4)(2), in the high-temperature phase I was studied using single-crystal neutron diffraction. It is known that the O atom involved in hydrogen bonding between neighbouring SO4 tetrahedra is disordered and takes a split-atom position, building a two-dimensional hydrogen-bond network in the (001) plane. The H atoms in these SO4-H-SO4 hydrogen bonds are disordered and hence refined with a split-atom model. Moreover, from the much larger anisotropic mean-square displacements of ammonium protons the NH <file type="gif" name="AYB_eb5009_mu1.gif"/> groups were refined with a reasonable split-atom model, and their motional behaviour was also analysed by rigid-body treatment. Finally, careful consideration was given to show possible supplementary proton migration between the ammonium protons and those of the hydrogen bonds in this high-temperature phase.

• 出版日期2011-4