Local structure in Ag3[Co(CN)6]: colossal thermal expansion, rigid unit modes and argentophilic interactions

Conterio, M. J. and Goodwin, A. L. and Tucker, M. G. and Keen, D. A. and Dove, M. T. and Peters, L. and Evans, J. S. O. (2008) Local structure in Ag3[Co(CN)6]: colossal thermal expansion, rigid unit modes and argentophilic interactions. Journal of Physics: Condensed Matter, 20 (25). p. 255225. DOI 10.1088/0953-8984/20/25/255225

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Abstract

Local structure in the colossal thermal expansion material Ag3[Co(CN)6] is studied here using a combination of neutron total scattering and reverse Monte Carlo (RMC) analysis. We show that the large thermal variations in cell dimensions occur with minimal distortion of the [Co(CN)6 ] coordination polyhedra, but involve significant flexing of the Co–CN–Ag–NC–Co linkages. We find real-space evidence in our RMC configurations for the importance of low-energy rigid unit modes (RUMs), particularly at temperatures below 150 K. Using a reciprocal-space analysis we present the phonon density of states at 300 K and show that the lowest-frequency region is dominated by RUMs and related modes. We also show that thermal variation in the energies of Ag...Ag interactions is evident in both the Ag partial pair distribution function and in the Ag partial phonon density of states. These findings are discussed in relation to the thermodynamic properties of the material.

Item Type: Article
Uncontrolled Keywords: 08AREP IA56 2008 P
Subjects: 03 - Mineral Sciences
Divisions: 03 - Mineral Sciences
Journal or Publication Title: Journal of Physics: Condensed Matter
Volume: 20
Page Range: p. 255225
Identification Number: 10.1088/0953-8984/20/25/255225
Depositing User: Sarah Humbert
Date Deposited: 16 Feb 2009 13:01
Last Modified: 23 Jul 2013 10:06
URI: http://eprints.esc.cam.ac.uk/id/eprint/210

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