1. Chemical Synthesis and Catalysis
• Reducing Agent:

Widely used in organic synthesis to reduce nitro compounds to amino compounds (e.g., reducing nitrobenzene to aniline).

Reduces precursors of azo dyes, or removes residual oxidizing agents during the dyeing process.

In inorganic chemistry, it reduces metal ions (e.g., reducing Fe³⁺ to Fe²⁺, Cr⁶⁺ to Cr³⁺) for analysis or purification.

• Catalyst:

Catalyst for organic reactions such as esterification and aldehyde/ketone reduction.

Used as a catalyst in polyurethane production (to accelerate reaction rate).

2. Electroplating Industry
• Tin Electroplating:

As a main component of acidic tin plating solutions, it provides Sn²⁺ ions to form a tin plating layer on the metal surface, used for corrosion protection, improved solderability, or decoration.

Especially suitable for electroplating electronic components (such as printed circuit boards and lead frames) to enhance solderability.

3. Glass and Ceramics Industry
• Glass Surface Treatment:

Used as a reducing agent in silver plating on glass surfaces (mirror making process), reducing silver ions (Ag⁺) to metallic silver to form a reflective layer.

Used in the “tin spraying” process of glass bottles and jars to enhance surface gloss and adhesion.

• Ceramic Coloring:

Used as a reducing agent to control the color development of metal oxides (such as copper and iron) in ceramic glazes, producing specific shades.

4. Analytical Chemistry
• Analytical Reagent:

Used in colorimetric determination of elements such as mercury and arsenic, by reduction to form colored substances or precipitates.

In environmental monitoring, it reduces heavy metal ions in water samples for detection.

• Masking Agent:

Used in conjunction with other reagents in titration analysis to eliminate interfering ions.

5. Polymer Industry
• PVC Stabilizer:

As a precursor for stannous chloride-based heat stabilizers, used in polyvinyl chloride (PVC) processing to inhibit decomposition (but this application is gradually being replaced by more environmentally friendly alternatives).

6. Energy and Batteries
• Lithium-ion Battery/Tin-based Battery Materials:

Used as a precursor to synthesize tin-based anode materials (such as SnO₂, Sn alloys) for high-performance lithium-ion batteries.

• Fuel Cells:

Used in research to prepare platinum-tin catalysts to improve fuel cell efficiency. 7. Pharmaceuticals and Biotechnology
• Radiopharmaceutical preparation:

In nuclear medicine, it is used as a reducing agent to label radioisotopes (such as ⁹⁹ᵐTc) to target molecules for disease diagnosis (e.g., bone scans).

• Dental materials:

Previously used in tin-silver alloy dental restorative materials, but now less commonly used.

8. Other Special Applications
• Metal surface treatment:

Activator before phosphating of steel, enhancing the adhesion of the phosphate coating.

Additive for electrolytic coloring of aluminum products.

• Photosensitive materials:

Used as a component of developers in traditional photography.

• Wood preservation:

Used in combination with other reagents for wood preservation treatment (inhibiting fungi and insects).