Conformational Polymorphism: the missing phase of 1,1,2,2-Tetrachloroethane (Cl2HC–CHCl2)
Halogenoethane derivatives are known to exhibit different polymorphs involving a different translational, orientational, and conformational order. The 1,1,2,2- tetrachloroethane (Cl2HC−CHCl2) exhibits a normal pressure orthorhombic phase β (space group P212121 with Z = 8 and Z′ = 2), formed by molec...
| Autores: | , , , , , |
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| Tipo de documento: | artigo |
| Estado: | Versão publicada |
| Data de publicação: | 2013 |
| País: | Argentina |
| Recursos: | Consejo Nacional de Investigaciones Científicas y Técnicas |
| Repositório: | CONICET Digital (CONICET) |
| Idioma: | inglês |
| OAI Identifier: | oai:ri.conicet.gov.ar:11336/25428 |
| Acesso em linha: | http://hdl.handle.net/11336/25428 |
| Access Level: | Acceso aberto |
| Palavra-chave: | Polymorphism Conformational Order Crystal Structure https://purl.org/becyt/ford/1.3 https://purl.org/becyt/ford/1 |
| Resumo: | Halogenoethane derivatives are known to exhibit different polymorphs involving a different translational, orientational, and conformational order. The 1,1,2,2- tetrachloroethane (Cl2HC−CHCl2) exhibits a normal pressure orthorhombic phase β (space group P212121 with Z = 8 and Z′ = 2), formed by molecules with one of the two gauche conformations. At high pressure, the stable polymorph is known to be monoclinic (space group P21/c, with Z = 2 and Z′ = 0.5), phase α, in which only the trans conformer appears. In this work, we demonstrate the existence of a normal pressure metastable polymorph, phase γ, for which the two gauche conformers show up in the asymmetric unit of a monoclinic (space group P21/c with Z = 8 and Z′ = 2) structure. The new phase γ is obtained by recrystallization upon heating the glass obtained after quench of the melt. It displays shorter type II Cl···Cl contacts than the high-pressure phase α due to attractive and directional interactions. |
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