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

Abstract

This version is available at https://strathprints.strath.ac.uk/26164/ Strathprints is designed to allow users to access the research output of the University of Strathclyde. Unless otherwise explicitly stated on the manuscript, Copyright © and Moral Rights for the papers on this site are retained by the individual authors and/or other copyright owners. Please check the manuscript for details of any other licences that may have been applied. You may not engage in further distribution of the material for any profitmaking activities or any commercial gain. You may freely distribute both the url (https://strathprints.strath.ac.uk/) and the content of this paper for research or private study, educational, or not-for-profit purposes without prior permission or charge.Any correspondence concerning this service should be sent to the Strathprints administrator: strathprints@strath.ac.ukThe Strathprints institutional repository (https://strathprints.strath.ac.uk) is a digital archive of University of Strathclyde research outputs. It has been developed to disseminate open access research outputs, expose data about those outputs, and enable the management and persistent access to Strathclyde's intellectual output. 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.

Structure and vibrational spectroscopy of methanesulfonic acid

“…A linear chain structure is commonly found in mineral acids and, in particular, is seen in the closely related molecules fluorosulfuric acid and trifluoromethanesulfonic acid [27]. In the previous literature, nitric acid was also believed to exist as dimers in its solid state [28,29], but more recent findings are that it too follows a catemer motif [30], hence it is not unreasonable to question the dimer MSA structure given the advances in the understanding of these solid-state structures. Moreover, inconsistencies between the predicted spectra for a MSA dimer and the observations have even been noted in previous work [12].…”

Crystal structure, thermal properties and detonation characterization of bis(5-amino-1,2,4-triazol-4-ium-3-yl)methane dinitrate

“…The structures and reported molecular volume differences of other amines are also reported to be different from their nitrates. For example, the symmetry of adeninium dinitrate (P2 1 2 1 2 1 ; Hardgrove et al, 1983) is higher than that of adenine (P2 1 /c; Mahapatra et al, 2008) and the ÁV between adeninium dinitrate (244.312 Å 3 ; Hardgrove et al, 1983) and adenine (150.196 Å 3 ;Mahapatra et al, 2008) is 94.116 Å 3 /molecule; and the symmetry of cytosine (P2 1 2 1 2 1 ; McClure & Craven, 1973) is higher than that of cytosinium nitrate (P1; Cherouana et al, 2003) (Allan et al, 2010) at low temperature. Thus, the nitrate improves the space utilization to a more compressed structure.…”

A new high-pressure polymorph of phosphoric acid

“…For a more thorough explanation of Hirshfeld surfaces and their corresponding fingerprint plots, the reader is referred to Spackman & Byrom (1997), but in brief, each fingerprint plot is unique to a given molecule and its features can be attributed to particular motifs in the crystal, notably the 'spiky' regions at shorter d e and d i distances (shortest distance to nuclei on the exterior and interior of the Hirshfeld surface, respectively) depict hydrogen bonding. Despite the very different packing between phases I and II, the fingerprint plots indicate only quite subtle changes in hydrogen-bonding distances, a feature also seen in nitric acid [see Figure 8 in paper by Allan et al (2010)]. More apparent is the decrease in distance of the centre of gravity of the fingerprint, suggesting a more efficient packing of phosphoric acid molecules overall, rather than decreasing intermolecular bonding distances.…”

“…For example, the manufacture of agricultural fertilizers accounts for most of the production of phosphoric acid (Schraü dter et al, 2000). Several crystal structures have been determined for these mineral acids at low temperature and high pressure: nitric acid crystallizes in different P2 1 =c structures, either below 232 K (Luzzati, 1951) or above 1.6 GPa (Lucas & Petitet, 1999;Allan et al, 2010) and sulfuric acid also has P2 1 =c symmetry at 0.7 GPa and a C2=c form below 283 K (Allan et al, 2002).…”