Pressure enhancement of negative thermal expansion behavior and induced framework softening in Zn(CN){sub 2}.
The pressure-dependent structure and functionality of the coordination framework material zinc cyanide, Zn(CN){sub 2}, has been explored using in situ neutron powder diffraction. A third-order Birch-Murnaghan equation of state fit to variable pressure (0?0.6 GPa) data collected at ambient temperature (K{sub 0} = 34.19(21) GPa, K{prime}{sub 0} = -6.0(7)) shows that, contrary to behavior observed for typical materials, the Zn(CN){sub 2} framework becomes more compressible at higher pressures. Variable temperature (50?300 K) data collected at 0.2 and 0.4 GPa indicate that the negative thermal expansion effect in Zn(CN){sub 2} becomes more pronounced at pressure with the coefficient of thermal expansion ({alpha} = dT/{ell}d{ell}) varying by ca. -1 x 10{sup -6} K{sup -1} per 0.2 GPa applied pressure up to an average (50-300 K) value of ?19.42(23) x 10{sup -6} K{sup -1} at 0.4 GPa. Both these unusual phenomena have been linked to increased framework flexibility at high pressure.
- Research Organization:
- Argonne National Laboratory (ANL)
- Sponsoring Organization:
- SC
- DOE Contract Number:
- AC02-06CH11357
- OSTI ID:
- 946414
- Report Number(s):
- ANL/XSD/JA-59550
- Journal Information:
- J. Am. Chem. Soc., Journal Name: J. Am. Chem. Soc. Journal Issue: 33 ; 2007 Vol. 129; ISSN JACSAT; ISSN 0002-7863
- Country of Publication:
- United States
- Language:
- ENGLISH
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