What is the correct name for the ionic compound with the formula NH_4_2S?

• A. Ammonium sulfur
• B. Ammonium sulfite
• C. Ammonium sulfate
• D. Ammonium sulfide

Answer: (D)

Verified step by step guidance

1. Identify the ions present in the compound NH_4_2S. The formula contains NH_4^+ (ammonium ion) and S^{2-} (sulfide ion).
2. Recognize that NH_4^+ is a polyatomic cation called ammonium, and S^{2-} is the sulfide anion, which is the simple ion form of sulfur with a -2 charge.
3. Understand that the compound is formed by combining two ammonium ions (each with a +1 charge) to balance the charge of one sulfide ion (with a -2 charge), resulting in the formula (NH_4)_2S.
4. Recall the naming convention for ionic compounds: the cation name is stated first (ammonium), followed by the anion name (sulfide).
5. Conclude that the correct name for NH_4_2S is ammonium sulfide, as it consists of ammonium cations and sulfide anions.