Ikkecrystallographic

Ikkecrystallographic is a nonstandard term used in some technical writings to describe data, methods, or phenomena that are not crystallographic in nature. The word appears as a portmanteau-like blend of ikke (not) from several Germanic languages with crystallographic, and it is not part of formal nomenclature. Because it is informal, its precise meaning can vary by author and discipline.

In practice, ikkecrystallographic may be used to separate analyses that do not rely on crystal lattices from those that do. For example, discussions of three-dimensional structures derived from cryo-electron microscopy, nuclear magnetic resonance, small-angle scattering, or computational models of non-crystalline materials might employ the term to emphasize a non-crystallographic origin. It can also appear in critiques of crystallographic assumptions when non-crystalline data are more appropriate or informative for a given problem.

The term is distinct from established concepts such as noncrystallographic symmetry (NCS) and from the general study of crystallography. Because ikkecrystallographic is informal, its interpretation can be ambiguous, and readers are advised to consult the author’s definition in context to understand how it is being used.

See also: crystallography; noncrystallographic symmetry; cryo-EM; NMR; SAXS; amorphous materials.