What is the correct name for FeS3? iron(III) trisulfide iron(III) sulfide diiron trisulfide iron sulfide iron(II) sulfide
The Correct Answer and Explanation is:
The correct name for FeS₃ is iron(III) trisulfide.
Explanation
To understand why FeS₃ is named iron(III) trisulfide, we need to examine both its chemical formula and naming conventions used in ionic compounds, particularly those involving transition metals.
1. Ionic Compounds and Transition Metals:
Iron is a transition metal, meaning it can form more than one type of ion. Common oxidation states of iron are +2 (iron(II)) and +3 (iron(III)). Therefore, it’s important to specify the oxidation state of the iron in the compound name using Roman numerals.
2. Sulfide Ion:
Sulfur forms the sulfide ion (S²⁻), which carries a -2 charge.
3. Determining Oxidation State:
The compound FeS₃ contains one iron atom (Fe) and three sulfur atoms (S). Since each sulfur has a -2 charge, the total negative charge from sulfur is: 3×(−2)=−63 \times (-2) = -63×(−2)=−6
To balance this, the single iron atom must have a +6 charge, which is chemically unlikely and unstable for iron in typical conditions. This suggests that FeS₃ is not a simple 1:3 ionic compound.
Instead, a more realistic interpretation is:
- The “3” in S₃ refers to three sulfur atoms each with a -2 charge (totaling -6).
- To balance -6, we would need two Fe³⁺ ions, each with a +3 charge.
Thus, the correct formula should be Fe₂S₃, not FeS₃, which corresponds to iron(III) sulfide.
However, if the formula FeS₃ is accepted as written (perhaps representing a more theoretical or structural compound), the correct name would be iron(III) trisulfide, assuming iron is in the +3 state and bonded to three sulfide ions.
Therefore, based on the nomenclature:
- Iron(III) indicates Fe³⁺
- Trisulfide indicates three S²⁻ ions
Hence, iron(III) trisulfide is the most chemically appropriate name for FeS₃.
