Noncrystallographic symmetry

From Online Dictionary of Crystallography

I wonder whether there is an official position of the nomenclature commission on this expression. "Noncrystallgraphic symmetry" to me is a symmetry that does not respect the restrictions imposed by the periodicity (in whatever space). For symmetry (or pseudo-symmetry, which does not change the essence) acting on a subspace of the crystal space (thus relating subunits) the term partial symmetry is used. A special case of partial symmetry is local symmetry. The corresponding operations are space groupoid operations. They cannot be called "noncrystallographic". In the ActaA celebration issued of the 60th anniversary of IUCr and Acta, published in January 2008, I have written a short review on this topic. I urge the Nomeclature Commission to take an official position on this point. --MassimoNespolo 11:19, 8 April 2008 (BST)