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The crystal structures of the low-temperature and high-pressure polymorphs of nitric acid

DOI: 10.1039/b923975h DOI Help
PMID: 20354626 PMID Help

Authors: Dave Allan (Diamond Light Source) , W. G. Marshall (Rutherford Appleton Laboratory) , D. J. Francis (ISIS Neutron Facility, STFC Rutherford Appleton Laboratory) , I. D. H. Oswald (University of Edinburgh) , C. Spanswick (University of Edinburgh) , C. R. Pulham (University of Edinburgh)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Dalton Transactions , VOL 39 (15) , PAGES 3736-3743

State: Published (Approved)
Published: January 2010

Abstract: A new high-pressure phase of pure nitric acid (HNO(3)) has been characterised at 1.6 GPa at room temperature by high-pressure neutron powder and X-ray single-crystal diffraction techniques. This is the first crystalline phase obtained upon compression of liquid nitric acid at room temperature and appears to be the stable phase up to pressures of at least 4 GPa. The crystal structure of this new phase shows some similarities to that of the low-temperature phase of nitric acid at ambient pressure, which has been redetermined as part of this study. Both structures share a herringbone packing of hydrogen-bonded molecular catemers, although the presence of disorder within the hydrogen bonds within one of the catemers of the low-temperature phase makes its structure comparatively more complex.

Subject Areas: Chemistry

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