What is the formula of aluminium sulfite, a compound related to aluminium and sulfur dioxide, and how does it compare to aluminium sulfide?
The term "aluminium Sulphur dioxide" does not refer to a standard, recognized chemical compound with a singular, simple formula. It appears to be a combination of "aluminium" and "sulfur dioxide" (SO2), which is a molecular gas. However, if this phrasing is intended to describe a compound involving aluminium, sulfur, and oxygen, the most chemically plausible interpretation leads to aluminium sulfite.
Understanding Aluminium Sulfite: A Plausible Interpretation
Aluminium sulfite is an ionic compound formed when aluminium ions (Al³⁺) combine with sulfite ions (SO₃²⁻). The sulfite ion itself is derived from sulfur dioxide (SO₂), which, when dissolved in water, forms sulfurous acid (H₂SO₃), the source of sulfite ions.
The chemical formula for aluminium sulfite is determined by balancing the charges of the ions:
- Aluminium ion: Al³⁺
- Sulfite ion: SO₃²⁻
To achieve electrical neutrality, two aluminium ions (2 × +3 = +6) combine with three sulfite ions (3 × -2 = -6).
| Compound Name | Chemical Formula | Key Characteristics |
|---|---|---|
| Aluminium Sulfite | Al₂(SO₃)₃ | Forms from Al³⁺ and SO₃²⁻ ions; typically a white solid. |
This compound is less common than aluminium sulfate but represents a direct chemical association between aluminium and the sulfur-oxygen group derived from sulfur dioxide.
Chemical Properties and Formation
Aluminium sulfite is expected to be a solid at room temperature. Its formation generally involves the reaction of an aluminium salt with a soluble sulfite, or the reaction of aluminium metal or aluminium oxide with sulfurous acid. Due to the nature of the sulfite ion, aluminium sulfite can be susceptible to oxidation, potentially forming aluminium sulfate in the presence of strong oxidizers.
For more information on sulfite compounds, you can refer to general chemistry resources like PubChem's entry on sulfite.
Distinguishing from Aluminium Sulfide
It is crucial to differentiate "aluminium Sulphur dioxide" (interpreted as aluminium sulfite) from aluminium sulfide, which is a distinct compound. Aluminium sulfide contains only aluminium and sulfur, without any oxygen.
The reference material provides specific details for aluminium sulfide:
| Compound Name | Chemical Formula | Molar Mass | Appearance | Density |
|---|---|---|---|---|
| Aluminium Sulfide | Al₂S₃ | 150.158 g/mol | Gray solid | 2.02 g/cm³ |
This compound is formed by the direct reaction of aluminium with sulfur. It is an ionic compound where aluminium ions (Al³⁺) combine with sulfide ions (S²⁻). The absence of oxygen in its structure makes it fundamentally different from aluminium sulfite or any compound implying "sulfur dioxide."
Other Related Aluminium-Sulfur-Oxygen Compounds
While aluminium sulfite is a plausible interpretation, another common compound of aluminium, sulfur, and oxygen is:
- Aluminium Sulfate (Al₂(SO₄)₃): This is a widely used industrial chemical, often referred to as alum. It features the sulfate ion (SO₄²⁻), which has one more oxygen atom than the sulfite ion. It is typically formed from the reaction of aluminium hydroxide with sulfuric acid.
In summary, while "aluminium Sulphur dioxide" is not a precise chemical name, understanding the chemistry of aluminium with sulfur and oxygen leads most directly to aluminium sulfite (Al₂(SO₃)₃), which must be clearly distinguished from aluminium sulfide (Al₂S₃).
