Role of entropic effects in controlling the polymorphism in formate ABX3 metal-organic frameworks.
Polymorphism in formate-based dense metal-organic frameworks with the general formula ABX3 is predicted by quantum chemical calculations and confirmed experimentally. In particular [NH3NH2]Zn(HCOO)3 crystallizes in two different polymorphs, a perovskite-like framework and a chiral structure with hexagonal channels. A detailed thermodynamic analysis reveals that both structures are very close in free energy and that entropy driven effects are responsible for stabilizing the channel structure.
Department of Materials Science and Metallurgy, University of Cambridge, Cambridge CB3 0FS, UK. gk354@cam.ac.uk akc30@cam.ac.uk.
Gregor
G
Kieslich
Shohei
S
Kumagai
Keith T
KT
Butler
Takuro
T
Okamura
Christopher H
CH
Hendon
Shijing
S
Sun
Masahiro
M
Yamashita
Aron
A
Walsh
Anthony K
AK
Cheetham