The name “Dialuminum Trisulfide” suggests that there are two aluminum atoms and three sulfur atoms in the compound, which is technically accurate regarding the molecular formula Al2S3. However, the use of the prefix “Di” for aluminum is not appropriate because aluminum is a metal and typically does not require numeric prefixes in its naming convention. Instead, metals are usually named using their elemental names and oxidation states when applicable.
The correct name for Al2S3 should be “Aluminum Sulfide.” In this case, we acknowledge that there are two aluminum ions (Al3+) combining with three sulfide ions (S2-) to balance the charge, resulting in the overall neutral compound. Naming it “Aluminum Sulfide” accurately reflects the composition without the unnecessary prefixes that apply to covalent compounds.