CAS 7664-39-3 · Unique Fluoride Chemistry · Restricted Chemical
Hydrofluoric Acid
HF (aq) · MW 20.01 g/mol · Weak Acid / Extreme Hazard
A uniquely hazardous acid with chemistry found nowhere else — HF is the only acid that dissolves silicon dioxide, making it irreplaceable in semiconductor manufacturing, glass etching, and petroleum refining. Despite being a weak acid (partially dissociating), HF penetrates skin and causes systemic fluoride toxicity. Texas-Chem supplies HF to qualified industrial customers with proper handling protocols in place.
Restricted sale — HF is supplied only to qualified industrial customers with documented handling procedures, appropriate PPE, and calcium gluconate antidote on-site.
Formula
HF (aq)
BP (pure HF)
19.5 °C
pKa
3.17 (weak acid)
Container
HDPE only
Structural Formula
Weak acid — strong hydrogen bonding causes partial dissociation; undissociated HF penetrates biological tissue
Critical Safety Warning
- NFPA Health
- 4 — Severe hazard
- NFPA Flammability
- 0 — Non-flammable
- NFPA Reactivity
- 1 — Slight hazard
- OSHA PEL (TWA)
- 3 ppm
- ACGIH TLV-Ceiling
- 0.5 ppm
- DOT Hazard Class
- 8 — Corrosive / 6.1 Toxic
- UN Number
- UN 1790
- Special Hazard
- Systemic fluoride toxicity — calcium gluconate antidote required on-site
HF burns may not be immediately painful. Calcium gluconate gel must be on-site. Seek immediate medical attention for any exposure. SDS required before purchase.
Grades & Packaging
Available Grades
Pack Sizes
HF must be stored in HDPE, PTFE, or wax-lined containers. Never use glass or standard stainless steel.
Physical & Chemical Properties
| Molecular Formula | HF (aq) |
| Molecular Weight | 20.01 g/mol (HF) |
| CAS Number | 7664-39-3 |
| Boiling Point | 19.5 °C (pure HF) / 112 °C (48%) |
| Melting Point | −83.6 °C (pure HF) |
| Flash Point | Non-flammable |
| Density | 1.15 g/cm³ (48% solution) |
| Vapor Pressure | 27 kPa at 20 °C (pure HF) |
| Solubility | Miscible with water in all proportions |
| pKa | 3.17 (weak acid — partially dissociates) |
| Odor | Sharp, pungent — detectable at 0.04 ppm |
| Container Material | HDPE, PTFE, or wax-lined steel only |
Industrial Applications
Semiconductor & Glass Etching
HF is the only acid that etches silicon dioxide — the fundamental dielectric in semiconductor devices. Used for cleaning silicon wafers, etching glass, and removing oxide layers in microelectronics fabrication.
Petroleum Alkylation
Catalyst in HF alkylation units that produce high-octane isooctane for gasoline blending. HF alkylation is widely used in US refineries alongside sulfuric acid alkylation.
Stainless Steel Pickling
Component of mixed acid pickling baths (HNO₃ + HF) for removing heat tint, scale, and weld discoloration from stainless steel. HF dissolves the chromium oxide scale that nitric acid alone cannot remove.
Fluorine Chemistry
Feedstock for producing fluorine-containing compounds including fluorocarbons, fluoropolymers (PTFE, PVDF), and pharmaceutical intermediates. HF is the primary industrial source of fluorine.
Mineral Processing
Dissolution agent for silicate minerals in ore processing and geochemical analysis. HF dissolves silica and silicate matrices that resist all other acids, enabling complete sample digestion.
Rust & Scale Removal
Highly effective rust remover for iron and steel — HF dissolves iron oxides and silicate scale rapidly. Used in industrial cleaning formulations where silica-based scale is present alongside rust.
Sourcing HF from Texas-Chem
- 35+ years supplying specialty acids to Texas industrial customers
- 48% and 70% technical grades for semiconductor, refining, and metal processing
- HDPE drum and tote packaging — no glass or standard steel containers
- SDS and handling documentation provided before shipment
- Qualified industrial customers only — contact us to discuss requirements
- Same-day quotes for qualified accounts