I was doing an investigation concerning polarity, when I noticed something odd:
The bond between Co and Cl is defined as ionic because it links a metallic cation with a nonmetal anion. However, if we use the polarity "guidelines", the bond should be polar covalent because the electronegativity difference between Co (EN: 1.9) and Cl (EN:3.2) is 1.3, as defined by the Ib Chemistry Data Booklet, First Assesment 2016, Third Edition.
How accurate are the polarity guidelines (0=nonpolar covalent, 0.5-1.7 or 0.5-2.0= polar covalent, >2.0=ionic)?