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The crystal structure of propanal has been determined using powder X-ray diffraction (PXRD), where this common laboratory aldehyde is measured to crystallise in spacegroup P21/a, Z = 4 with a unit cell a = 8.9833(6) Å, b = 4.2237(2) Å, c = 9.4733(6) Å and β = 97.508(6)°, resulting in a volume of 356.37(4) Å3 at 100 K and atmospheric pressure. The thermal expansion observed from 100 K until the sample melted (∼164 K) was found to be anisotropic. An additional neutron diffraction study was carried out, reaching a temperature of 3 K and found no further phase transformations from the determined structure at lower temperatures. The investigated temperature regime correlates to astronomical surfaces, including outer Solar System bodies and interstellar dust mantles, where propanal is thought to be generated by energetic processing of composite molecular ices. Results from the structure determination were applied to model propanal ice using periodic density functional theory for the calculation of intermolecular frequencies, where the simulated far-infrared spectrum of solid propanal can now be used for future molecular astronomy. [ABSTRACT FROM AUTHOR]

Y(btc) (btc = 1,3,5-benzenetricarboxylate) is a metal-organic framework that exhibits significant adsorption of industrially-relevant gases such as H2, CH4, and O2. Previous studies have noted a surprising lack of close interactions between the adsorbed guest molecules and Y, despite the apparent availability of a "bare-metal" binding site. We have extended our previous work in a detailed investigation of the adsorption behaviours of CO2, CD4, and O2 in Y(btc) over a range of concentrations using in situ neutron powder diffraction methods. The O-Y-O bond angles enclosing the bare-metal site are found to change considerably depending on the type and quantity of guest molecules present. Multiple binding sites are found for each guest species, and the largest changes in O-Y-O angles are accompanied by changes in the filling sequences of the binding sites, pointing to an important interplay between guest-induced framework distortions and binding site accessibility. These results suggest the potential for coordinatively flexible rare-earth metal centres to promote guest-selective binding in metal-organic frameworks. [ABSTRACT FROM AUTHOR]

Neutron powder diffraction measurements were carried out on the evacuated and CO2-loaded Prussian blue analogue, Fe3[Co(CN)6]2, identifying two distinct CO2 adsorption sites: site A, in which CO2 uniquely bridges between two bare-metal sites, and site B, in which it interacts in a face capping motif. The saturation of site A at low loadings of CO2 demonstrates the favourable nature of the interaction of CO2 with bare-metal sites within the material. [ABSTRACT FROM AUTHOR]

The crystal structure of propanal has been determined using powder X-ray diffraction (PXRD), where this common laboratory aldehyde is measured to crystallise in spacegroup P 21/ a , Z = 4 with a unit cell a = 8.9833(6) Å, b = 4.2237(2) Å, c = 9.4733(6) Å and β = 97.508(6)°, resulting in a volume of 356.37(4) Å 3 at 100 K and atmospheric pressure. The thermal expansion observed from 100 K until the sample melted (∼164 K) was found to be anisotropic. An additional neutron diffraction study was carried out, reaching a temperature of 3 K and found no further phase transformations from the determined structure at lower temperatures. The investigated temperature regime correlates to astronomical surfaces, including outer Solar System bodies and interstellar dust mantles, where propanal is thought to be generated by energetic processing of composite molecular ices. Results from the structure determination were applied to model propanal ice using periodic density functional theory for the calculation of intermolecular frequencies, where the simulated far-infrared spectrum of solid propanal can now be used for future molecular astronomy.