Interrelationship “composition - structure - property” for Cu- and Ge-bearing sulfides

The relation “composition - structure - property” is considered for sets of >;120 Cu-bearing and >;90 Ge-containing ternary noncentrosymmetric sulfide crystals. These crystals are distributed on the plane of the shortest metal-sulphur chemical bond lengths over an area covered by a rosette of three partly crossing ellipses. The distribution of ferroelastic and paraelastic sulfides over the ellipses is different. It is shown that small part of trigonal and monoclinic Ge-bearing sulfides are possessing noticeable χ⁽²⁾ level and only three polar and non-polar crystals related to this family are characterized by pronounced χ⁽²⁾ level.