Shortest chemical bond length as a criterion for searching new noncentrosymmetric phosphate crystals

A set of available experimental data on crystal structure of simple and binary phosphates, >270 compounds, have been observed with using criterion of the shortest chemical bond between cations and oxygen. A correlation between the magnitude of nonlinear optical susceptibility χ(2) and the combination of chemical bonds has been discussed. Criteria for searching phosphate compounds with high χ(2) have been revealed.