Select the odd one out.

${\mathit{CCl}}_4$ is the odd one out.
${\mathit{CCl}}_4$is the covalent compound, formed by the bonding of carbon and chlorine.

 In this molecule there are four atoms of chlorine that is prefix tetra, which is for the identification of the number of atoms  of each element in the molecule. There are two different kinds of bonds that can form between atoms in a molecule: ionic and covalent. 

Whether an atom is a metal or a non-metal depends on the nature of the ionic and covalent connections. It is an ionic bond if one of them is a metal and the other is non-metal, and a covalent bond if neither of them is a metal. The other are the electrovalent compounds.