Question

Is `CuCl_2` an ionic salt or covalent molecule?

Answer 1

`CuCl_2` is an ionic salt.

Explanation:

Chlorine has a high electro negativity of 3.0. Copper like most metals has a low electro negativity, So the bonding is ionic making the compound an ionic salt.

Answer 2

`"CuCl"_2` is a covalent compound.

Explanation:

Here is my reasoning.

A. Electronegativity differences

The electronegativity of `"Cl"` is 3.16; the electronegativity of Cu is 1.90.

`ΔEN = "3.16 - 1.90" = 1.26`.

This is much less than the normal cutoff value of 1.7 for declaring a compound ionic.

It predicts only about 33 % ionic character — i.e. a polar covalent `"Cu-Cl"` bond.

B. Crystal structure

The crystal consists of `"Cu"` and `"Cl"` atoms arranged in a 3D array, and each `"Cu"` atom is coordinated to 6 `"Cl"` atoms.

(From Chemistry LibreTexts)

C. Colour

`"CuCl"_2` has a brown colour.

(From Amazing Rust.com)

In contrast, `"CuCl"_2·"2H"_2"O"` contains hydrated copper(II) ions, with their characteristic blue colour.