Is CuCl_2 an ionic salt or covalent molecule?

2 Answers
Jan 10, 2017

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.

Jan 27, 2017

"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.

CuCl2CuCl2
(From Chemistry LibreTexts)

C. Colour

"CuCl"_2 has a brown colour.

ComparisonComparison
(From Amazing Rust.com)

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