# Is CuCl_2 an ionic salt or covalent molecule?

Jan 10, 2017

$C u C {l}_{2}$ 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

${\text{CuCl}}_{2}$ is a covalent compound.

#### Explanation:

Here is my reasoning.

A. Electronegativity differences

The electronegativity of $\text{Cl}$ 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 $\text{Cu-Cl}$ bond.

B. Crystal structure

The crystal consists of $\text{Cu}$ and $\text{Cl}$ atoms arranged in a 3D array, and each $\text{Cu}$ atom is coordinated to 6 $\text{Cl}$ atoms.

(From Chemistry LibreTexts)

C. Colour

${\text{CuCl}}_{2}$ has a brown colour.

(From Amazing Rust.com)

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