What is the correct formula unit for the ionic compound, lithium sulfide?

? Li2S
? LiS2
? LiS8
? LaS2
? LiS

1 answer

The correct formula unit for the ionic compound lithium sulfide is Li2S. This is because lithium (Li) has a +1 charge and sulfur (S) has a -2 charge, so you need two lithium ions to balance one sulfide ion, resulting in the formula Li2S.