Ionic compounds are named according to their ions, including the charge on the cation if it is variable. Molecular compounds are named with prefixes. Dichlorine trioxide Cl2O3 Manganese(III) oxide Mn2O3 Oxygen difluoride OF2 Iron(II) fluoride FeF2 Hydrogen sulfide H2S Magnesium hydride MgH2 Molecular Ionic Add the valence electrons of all atoms.
››More information on molar mass and molecular weight. In chemistry, the formula weight is a quantity computed by multiplying the atomic weight (in atomic mass units) of each element in a chemical formula by the number of atoms of that element present in the formula, then adding all of these products together.
A B; lithium fluoride: LiF: lithium chloride: LiCl: lithium bromide: LiBr: lithium iodide: LiI: lithium oxide: Li2O: lithium sulfide: Li2S: lithium nitride: Li3N ...