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arXiv · 1204.3007

PASCal: A principal-axis strain calculator for thermal expansion and compressibility determination

Matthew J. Cliffe·Andrew L. Goodwin
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Abstract

We describe a web-based tool (PASCal; Principal Axis Strain Calculator) aimed at simplifying the determination of principal coefficients of thermal expansion and compressibilities from variable-temperature and variable-pressure lattice parameter data. In a series of three case studies, we use PASCal to re-analyse previously-published lattice parameter data and show that additional scientific insight is obtainable in each case. First, the two-dimensional metal-organic framework Cu-SIP-3 is found to exhibit the strongest area-negative thermal expansion (NTE) effect yet observed; second, the widely-used explosive HMX exhibits much stronger mechanical anisotropy than had previously been anticipated, including uniaxial NTE driven by thermal changes in molecular conformation; and, third, the high-pressure form of the mineral malayaite is shown to exhibit a strong negative linear compressibility (NLC) effect that arises from correlated tilting of SnO6 and SiO4 coordination polyhedra.

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Matthew J. Cliffe, Andrew L. Goodwin. 2012-10-23. PASCal: A principal-axis strain calculator for thermal expansion and compressibility determination. https://doi.org/10.1107/s0021889812043026

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