The name "Magnesium Dichloride" is incorrect for the compound MgCl2 because the compound is not composed of magnesium and chlorine only in a 1:1 ratio. The compound is actually composed of one Magnesium atom (Mg) and two Chlorine atoms (Cl2).
The correct name for the compound MgCl2 is Magnesium Chloride, which describes the chemical formula accurately. The prefix "di-" refers to two atoms and is used when there are two atoms of the same element in a compound, In this case, there are two chlorine atoms in MgCl2.