title: Hidden negative linear compressibility in lithium l-tartrate.
abstract: By decoupling the mechanical behaviour of building units for the first time in a wine-rack framework containing two different strut types, we show that lithium l-tartrate exhibits NLC with a maximum value, Kmax= -21 TPa-1, and an overall NLC capacity, χNLC= 5.1%, that are comparable to the most exceptional materials to date. Furthermore, the contributions from molecular strut compression and angle opening interplay to give rise to so-called "hidden" negative linear compressibility, in which NLC is absent at ambient pressure, switched on at 2 GPa and sustained up to the limit of our experiment, 5.5 GPa. Analysis of the changes in crystal structure using variable-pressure synchrotron X-ray diffraction reveals new chemical and geometrical design rules to assist the discovery of other materials with exciting hidden anomalous mechanical properties.
authors.affiliation: Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford, OX1 3QR, UK. Hamish.yeung@chem.ox.ac.uk and WPI International Center for Materials Nanoarchitectonics (MANA), National Institute of Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan and International Center for Young Scientists (ICYS), National Institute of Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan.
authors.forename: Hamish H-M
authors.identifier: http://orcid.org/0000-0003-1629-6275
authors.initials: HH
authors.lastname: Yeung
authors.affiliation: EaStChem School of Chemistry and Centre for Science at Extreme Conditions, University of Edinburgh, David Brewster Road, Joseph Black Building, Edinburgh EH9 3FJ, UK. s.moggach@ed.ac.uk and Centre for Doctoral Training in Plastic Electronics, Centre for Plastic Electronics, Imperial College London, Prince Consort Road, London, SW7 2BZ, UK.
authors.forename: Rebecca
authors.initials: R
authors.lastname: Kilmurray
authors.affiliation: EaStChem School of Chemistry and Centre for Science at Extreme Conditions, University of Edinburgh, David Brewster Road, Joseph Black Building, Edinburgh EH9 3FJ, UK. s.moggach@ed.ac.uk.
authors.forename: Claire L
authors.initials: CL
authors.lastname: Hobday
authors.affiliation: EaStChem School of Chemistry and Centre for Science at Extreme Conditions, University of Edinburgh, David Brewster Road, Joseph Black Building, Edinburgh EH9 3FJ, UK. s.moggach@ed.ac.uk.
authors.forename: Scott C
authors.initials: SC
authors.lastname: McKellar
authors.affiliation: Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge, CB3 0FS, UK.
authors.forename: Anthony K
authors.initials: AK
authors.lastname: Cheetham
authors.affiliation: Diamond Light Source Ltd, Harwell Science and Innovation Campus, Didcot, OX11 0DE, UK.
authors.forename: David R
authors.initials: DR
authors.lastname: Allan
authors.affiliation: EaStChem School of Chemistry and Centre for Science at Extreme Conditions, University of Edinburgh, David Brewster Road, Joseph Black Building, Edinburgh EH9 3FJ, UK. s.moggach@ed.ac.uk.
authors.forename: Stephen A
authors.initials: SA
authors.lastname: Moggach