Number of generating elements in space group of a crystal

The numerical parameter Q (the critical coordination number), which characterizes the smallest number of contacts sufficient for the formation of this structure is constructed based on the power |g| of the minimal set of generating elements | g | of space group G . The calculation of |g| for space groups with the lowest isometric systems was carried out according to the developed algorithm. The structural classes of crystals corresponding to Q = 1 were derived. The selection of relevant structures in the Cambridge database (CSD) was carried out and typical representatives were considered.