6533b7d3fe1ef96bd125ff7a
RESEARCH PRODUCT
Molecular association in low-temperature and high-pressure polymorphs of 1,1,1,2-tetrachloroethane
Andrzej KatrusiakMaciej Bujaksubject
CrystallographyIsochoric processChemistryIntermolecular forceMolecular symmetryMelting pointMoleculeIsobaric processGeneral Materials ScienceGeneral ChemistryCondensed Matter PhysicsIsothermal processMonoclinic crystal systemdescription
Interactions and aggregation of 1,1,1,2-tetrachloroethane molecules, Cl3CCH2Cl, have been investigated at low temperature and high pressure. Isobaric and isochoric crystallizations led to two polymorphs, characterized by single-crystal X-ray diffraction. The low-temperature polymorph α is monoclinic, space group C2/c, with molecules orientationally disordered in two sites at the temperature independent 70:30 rate. In isothermal conditions (295 K) 1,1,1,2-tetrachloroethane freezes at 0.73 GPa. The high-pressure polymorph β is monoclinic, space group P21/c, with the molecules fully ordered. The molecular aggregation at varied thermodynamic conditions results from the interplay of halogen interactions, molecular symmetry and packing efficiency of the molecules. The intermolecular interactions in 1,1,1,2- and 1,1,2,2-tetrachloroethane isomers have been correlated with their melting points, lower by ca. 25 K for the former compound.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2010-01-01 | CrystEngComm |