Chromium (III) Potassium Sulfate Dodecahydrate ( Chromium Potassium Sulfate ; Chrome Alum ) - 1000g

Chromium(III) Potassium Sulfate Dodecahydrate

Other Names: Chrome Alum, Chromium Potassium Sulfate
Chemical Formula: KCr(SO₄)₂·12H₂O
Molar Mass: 499.41 g/mol
CAS Number: 7788-99-0
Appearance: Dark purple to violet crystalline solid
Odor: Odorless

Chrome alum is a double sulfate salt of potassium and chromium in the +3 oxidation state. It typically appears as dark violet octahedral crystals and is highly soluble in water. It is commonly used in chemical synthesis, leather tanning, and as a laboratory reagent.

Chemical and Physical Properties

• Density: ~1.83 g/cm³

• Melting Point: Decomposes before melting

• Solubility in Water: Soluble (~190 g/L at 20 °C)

• Solubility in Organic Solvents: Insoluble

• Stability: Stable under normal conditions; hygroscopic

• Color: Dark purple to red-violet (due to d–d transitions in Cr³⁺)

Applications

• Leather Industry: Used in leather tanning for its ability to cross-link collagen fibers.

• Chemical Synthesis: Employed as a chromium(III) source in coordination chemistry and material science.

• Laboratory Reagent: Used in analytical chemistry, crystallography, and for demonstration of crystal formation.

• Pigment and Dye Industry: Utilized in production of certain specialty pigments and mordants.

• Electroplating: Occasionally used in chromium-based electrochemical processes.

Safety

Signal Word: ⚠️ Warning

Hazard Statements:

• H319: Causes serious eye irritation

• H332: Harmful if inhaled

• H335: May cause respiratory irritation

• H351: Suspected of causing cancer (chromium compounds, category 2)

• H411: Toxic to aquatic life with long lasting effects

Precautionary Statements:

• P261: Avoid breathing dust

• P271: Use only outdoors or in a well-ventilated area

• P280: Wear protective gloves, protective clothing, eye and face protection

• P304+P340: IF INHALED: Remove person to fresh air and keep comfortable for breathing

• P305+P351+P338: IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses if present and easy to do. Continue rinsing

• P501: Dispose of contents/container in accordance with local regulations

Handling and Storage

• Handling: Avoid generation of dust. Use proper personal protective equipment (PPE). Work in a well-ventilated area or fume hood.

• Storage: Store in a cool, dry, well-ventilated area. Keep container tightly closed and protected from moisture. Separate from acids and reducing agents.

Environmental Considerations

Chrome alum is toxic to aquatic organisms and should not be released into the environment. Dispose of waste responsibly in compliance with hazardous chemical regulations.