Hydrofluoric acid CAS 7664-39-3

Hydrofluoric acid (HF), with the CAS number 7664-39-3, is a highly corrosive and toxic solution of hydrogen fluoride in water. It is a colorless liquid that is known for its ability to etch glass and metals, making it valuable in various industrial applications, particularly in semiconductor manufacturing and mineral processing.
Chemical Properties
Chemical Formula: HF (aqueous solution)
Molecular Weight: Approximately 20.01 g/mol
Density: About 1.15 g/mL for a 48% solution
Appearance: Colorless liquid with a pungent odor
Hydrofluoric acid is typically found in concentrations ranging from 48% to nearly 100% in industrial settings. The most common concentration used is around 49%.
Uses
Hydrofluoric acid is primarily used for:
Etching Glass: Its ability to react with silica makes it effective for glass etching.
Semiconductor Fabrication: HF is crucial in the production of silicon wafers and other electronic components.
Production of Fluorine Compounds: It serves as a precursor in the synthesis of various organofluorine compounds, including pharmaceuticals and fluoropolymers like Teflon.
Health Hazards
Despite its utility, hydrofluoric acid poses significant health risks:
Tissue Damage: HF can penetrate the skin and cause severe burns, leading to necrosis and systemic toxicity. The fluoride ions bind with calcium and magnesium in the body, potentially causing life-threatening conditions such as cardiac arrhythmias and respiratory failure.
Delayed Symptoms: Symptoms of exposure may not appear immediately, especially with lower concentrations, which can lead to severe injuries before medical attention is sought.
Fatal Concentrations: Concentrated solutions (≥50% HF) can be lethal even with minimal skin exposure, highlighting the need for immediate medical intervention in cases of exposure.
Safety Precautions
When handling hydrofluoric acid, strict safety protocols must be followed:
Personal Protective Equipment (PPE): Use appropriate gloves, goggles, and protective clothing to prevent skin and eye contact.
Emergency Procedures: Have calcium gluconate gel available for immediate treatment of skin exposure, and ensure that emergency medical services are informed about the exposure to HF.
In summary, hydrofluoric acid is a powerful chemical with significant industrial applications but also poses serious health risks that require careful handling and immediate response in case of exposure.