Open AccessCrystal structure of propionitrile (CH 3 CH 2 CN) determined using synchrotron powder X‐ray diffraction
Author(s) -
Brand Helen E. A.,
Gu Qinfen,
Kimpton Justin A.,
Auchettl Rebecca,
Ennis Courtney
Publication year - 2020
Publication title -
journal of synchrotron radiation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.172
H-Index - 99
ISSN - 1600-5775
DOI - 10.1107/s1600577519015911
Subject(s) - propionitrile , thermal expansion , powder diffraction , synchrotron , diffraction , x ray crystallography , nitrile , crystallography , x ray , molecule , anisotropy , materials science , chemistry , acetonitrile , physics , optics , composite material , organic chemistry
The structure and thermal expansion of the astronomical molecule propionitrile have been determined from 100 to 150 K using synchrotron powder X‐ray diffraction. This temperature range correlates with the conditions of Titan's lower stratosphere, and near surface, where propionitrile is thought to accumulate and condense into pure and mixed‐nitrile phases. Propionitrile was determined to crystallize in space group, Pnma (No. 62), with unit cell a = 7.56183 (16) Å, b = 6.59134 (14) Å, c = 7.23629 (14), volume = 360.675 (13) Å 3 at 100 K. The thermal expansion was found to be highly anisotropic with an eightfold increase in expansion between the c and b axes. These data will prove crucial in the computational modelling of propionitrile–ice systems in outer Solar System environments, allowing us to simulate and assign vibrational peaks in the infrared spectra for future use in planetary astronomy.