Pressure-induced amorphization and polyamorphism: Inorganic and biochemical systems D. Machon a,⇑ , F. Meersman b,c , M.C. Wilding d , M. Wilson e , P.F. McMillan c a Institut Lumière Matière, UMR5306, Université Lyon 1-CNRS, Université de Lyon, 69622 Villeurbanne cedex, France b Department of Chemistry and Materials Chemistry Centre, Christopher Ingold Laboratories, University College London, 20 Gordon Street, London WC1H 0AJ, UK c Department of Chemistry, University of Antwerp, Groenenborgerlaan, 2020 Antwerp, Belgium d Institute of Mathematical and Physical Sciences, Aberystwyth University, Aberystwyth SY23 3BZ, UK e Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, UK article info Article history: Received 20 June 2013 Received in revised form 2 December 2013 Accepted 3 December 2013 Available online 14 December 2013 abstract Pressure-induced amorphization (PIA) is a phenomenon that involves an abrupt transition between a crystalline material and an amorphous solid through application of pressure at tempera- tures well below the melting point or glass transition range. Amor- phous states can be produced by PIA for substances that do not normally form glasses by thermal quenching. It was first reported for ice I h in 1984 following prediction of a metastable melting event associated with the negative initial melting slope observed for that material. The unusual phenomenon attracted intense inter- est and by the early 1990s PIA had been reported to occur among a wide range of elements and compounds. However, with the advent of powerful experimental techniques including high resolution synchrotron X-ray and neutron scattering combined with more precise control over the pressurization environment, closer exam- ination showed that some of the effects previously reported as PIA were likely due to formation of nanocrystals, or even that PIA was completely bypassed during examination of single crystals or materials treated under more hydrostatic compression conditions. Now it is important to understand these results together with related discussions of polyamorphic behavior to gain better under- standing and control over these metastable transformations occur- ring in the low temperature range where structural relaxation and 0079-6425/$ - see front matter Ó 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.pmatsci.2013.12.002 ⇑ Corresponding author. E-mail address: denis.machon@univ-lyon1.fr (D. Machon). Progress in Materials Science 61 (2014) 216–282 Contents lists available at ScienceDirect Progress in Materials Science journal homepage: www.elsevier.com/locate/pmatsci