Question

What are covalent halides?

Answer 1

Metal halides are compounds between metals and halogens. Some, such as sodium chloride are ionic, while others are covalently bonded. Covalently bonded metal halides may be discrete molecules, such as uranium hexafluoride, or they may form polymeric structures, such as palladium chloride.

The most covalent halide is iodide, as astatide is practically artificial (there’s only about a gram of astatine on Earth at any one time in total[1]).

This is because it is the least electronegative, so in a covalent compound it has the least polarising effect.

Polarity in a covalent bond is ionic character caused by a difference in electronegativity between two atoms*, so if it is the least polarising element, it is the most covalent.

Answer 2

covalent halide is iodide, as astatide is practically artificial (there’s only about a gram of astatine on Earth at any one time in total

This is because it is the least electronegative, so in a covalent compound it has the least polarising effect.

Polarity in a covalent bond is ionic character caused by a difference in electronegativity between two atoms, so if it is the least polarising element, it is the most covalent.