What is the formula and molar mass of beryllium chloride?

##BeCl_2## has a molar mass of 79.9176 amu

Recall that the formula mass is the sum of the atomic weights of the atoms in substance while it is in its empirical formula, and that the is the weight of precisely one mol of the substance.

We have Beryllium chloride which is an ionic compound that forms a crystal lattice, the formula ##BeCl_2## tells us that ##BeCl_2## is the simplest repeating unit that forms the crystal lattice.

Since this is an ionic compound, ##BeCl_2## is a formula unit, not a molecular formula.

It's mass is 79.9175 amu.