The triplicity of the installation of trigonaloid crystals

Abstract

I mean to limit myself only to the simpler conclusions that I use in lectures (see article). From this triplicity we deduce the need for restrictions on the main numbers of the symbol of the complex, that is, that for an octahedral structure one cannot accept a number greater than 63 1/2°, for a hexahedral one one can accept only numbers within 45° - 63 1/2°, and for dodecahedral only numbers greater than 45°.