Paracrystal

A paracrystal is a kind of partially disordered crystal; wherein some forms of short and medium-range order of the lattice is present, but where long-range ordering (in at least one direction) does not exist. Many real materials are best though of as paracrystals (and not perfect crystals). I.e. in real materials there is often a well-defined local packing, essentially a unit cell, but this packing does not persist indefinitely without some kind of distortion.

In scattering, paracrystal disorder leads to specific kinds of peak broadening and peak shapes.

See Also

• Wikipedia: Paracrystalline
• A.M. Hindeleh and R. Hosemann Paracrystals representing the physical state of matter J. Phys. C: Solid State Phys. 1988, 21, 4155 doi: 10.1088/0022-3719/21/23/004
• Buckley Crist Small-angle x-ray scattering of semicrystalline polymers. I. Review of existing models J. Poly. Sci.: Poly. Phys. 1973, 11 (4), 635-661 doi: 10.1002/pol.1973.180110403
• J. L. Eads and R. P. Millane Diffraction by the ideal paracrystal Acta. Cryst. 2001, A57, 507-517 doi: 10.1107/S0108767301006341
  • Richard Welberry Discussion of: Diffraction by the ideal paracrystal
• Rodrigo Noriega, Jonathan Rivnay, Koen Vandewal, Felix P. V. Koch, Natalie Stingelin, Paul Smith, Michael F. Toney & Alberto Salleo A general relationship between disorder, aggregation and charge transport in conjugated polymers Nature Materials 2013, 12, 1038–1044. doi: 10.1038/nmat3722
• Karol Vegso, Peter Siffalovic, Matej Jergel, Eva Majkova, Teodora Kocsis, Monika Benkovicova, Stefan Luby, Ignac Capek, Jan Perlich and Stephan V. Roth Application of the paracrystal model to GISAXS analysis of the 3D self-assembled nanoparticle crystals Physica Status Solidi (b) 2014, 251 (6), 1169-1177. doi: 10.1002/pssb.201350347