Is #CuCl_2# an ionic salt or covalent molecule?

2 Answers
Jan 10, 2017

Answer:

#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

Answer:

#"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.

CuCl2
(From Chemistry LibreTexts)

C. Colour

#"CuCl"_2# has a brown colour.

Comparison
(From Amazing Rust.com)

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