What Is Tin Oxide?
Tin oxide, appearing as a black-gray or black crystalline powder, is an inorganic compound with diverse applications.
With the chemical formula SnO and a molecular weight of 134.71, tin oxide melts at 1,080℃. It is governed by the Industrial Safety and Health Law, designated as a Hazardous and Noxious Substance for labeling and notification, without implications from laws like the Fire Service Law.
Uses of Tin Oxide
As a versatile compound, tin oxide serves as a reducing agent, a catalyst base, and in organic synthesis. It contributes to pigments, ferrous tin salts production, and tin plating replenishment. Additionally, it stabilizes PVC, preventing degradation over time—a crucial aspect for materials used in daily products and infrastructure.
Properties of Tin Oxide
Tin oxide manifests in several forms, including tin (II) oxide with a stable dark blue or metastable red state, reflecting tin’s +2 oxidation state.
Structure of Tin Oxide
The black α-SnO variant displays a tetrahedral PbO layer structure, mirroring the rare mineral lomarkite. Its asymmetry, influenced by the anti-bonding interaction between tin’s 5s orbital and oxygen’s 2p orbital, leads to an electronic band gap between 2.5 and 3 eV.
Other Information on Tin Oxide
1. Reactivity of Tin Oxide (II)
Tin (II) oxide reacts vividly in air, transforming into tin (IV) oxide with a dark green flame, and undergoes disproportionation in inert atmospheres. Its amphoteric nature allows reactions with both acids and bases, forming various tin salts and complexes, and contributes to copper red glass production.
2. Synthesis of Tin Oxide (II)
Dark blue tin (II) oxide is synthesized from tin (II) oxide hydrate via alkaline reaction, while red tin (II) oxide emerges from ammonia-treated tin (II) salts. Tin (II) oxide also derives from tin (II) oxalate decomposition in controlled, airless conditions.
3. About Tin Oxide (IV)
Tin (IV) oxide, or tin dioxide, SnO2, is an antimagnetic amphoteric oxide. As a colorless powder, it forms a rutile-type structure, rendering it an oxygen-deficient n-type semiconductor. Tin (IV) oxide hydrates, varying in water content by particle size, illustrate the compound’s adaptability.