1. Cation First: In ionic compounds, the cation (positively charged ion) is named first, followed by the anion (negatively charged ion). Aluminum forms a cation (Al³⁺), while sulfur forms an anion (S²⁻).
2. Anion Suffix: The anion is named with an "-ide" suffix.
3. Roman Numerals: Aluminum can form multiple oxidation states, but in this case, it has a +3 charge. Since the charge is predictable, Roman numerals are not used.
Therefore, the correct name for the ionic compound formed between sulfur and aluminum is aluminum sulfide.
