Investigation of the changes in hydrogen bonding accompanying the structural reorganization at 103K in Ammonium iodate

Jones

doi:10.1107/s2052520619000325

Investigation of the changes in hydrogen bonding accompanying the structural reorganization at 103K in Ammonium iodate

Jones

Authors

Richard Jones r.h.jones@keele.ac.uk

Abstract

Neutron powder diffraction has been used to observe the changes in hydrogen bonding that occur
as a function of temperature in ND4IO3, and thus determine the structural features that occur during
the low temperature (103 K) phase transition. We show that in the deuterated material the change
is not a phase change per se but rather a structural reorganization in which the hydrogen bonding
becomes “firmly locked in” at the phase transition temperature, and stays in this configuration upon
further cooling to 4.2 K. In addition, both the differences and changes in the axial thermal
expansion coefficients in the region 100 – 290K can be explained by the changes involving both the
hydrogen bonding and secondary I---O halogen bonds.

Acceptance Date	Jan 8, 2019
Publication Date	Apr 1, 2019
Journal	Acta Crystallographica Section B: Structural Science
Print ISSN	0108-7681
Publisher	International Union of Crystallography
DOI	https://doi.org/10.1107/s2052520619000325
Keywords	neutron diffraction; hydrogen bonding; phase transitions; variable temperature; ammonium ion.
Publisher URL	https://doi.org/10.1107/s2052520619000325