posted by Boo Boo .
Approximately what electronegativity difference would you expect for a polar covalent bond?
A difference of about 1.7 or 1.8 is 50% more or less ionic/covalent. I count those around 1.0 as polar covalent or about 75% covalent/25% ionic. Obviously those compounds, many of them, fall within the polar covalent range.