The concept of geometrical frustration was considered; in particular regard to the case of frustrated icosahedral order. The curved space approach permitted relaxation of the frustration at the price of curving the underlying space. Topological defects were then introduced in order to produce a realistic structure in R3. Attention was focussed here on the description of two types of large-cell crystalline structures with frustrated order. These were the metallic Frank–Kasper alloys and the cholesteric blue phases. Both structures could be described as being a periodic array of disclination line-defects threading a medium with (slightly-deformed) local and medium-range ordering.

Geometrical Frustration and Defects in Condensed Matter Systems. R.Mosseri: Comptes Rendus Chimie, 2008, 11[3], 192-7