For twenty-one 8-N (octet) compounds, we consider the dependence of the Poisson ratio upsilion} on fractional covalent-ionic character estimated from atomic electronegativites. Compounds with ionicity approaching 1.0 show Poisson ratios near the upper bound: υ = 0.5. Increasing covalency moves υ toward zero, the effective lower bound. Especially, we focus on tetrahedral semiconductors where ionicity rannges from 0 to 0.6. We find that the Poisson ratio increases with increasing ionicity.
Poisson Ratio and Covalency - Ionicity
Handbook of Elastic Properties of Solids, Fluids, and Gases ,