Hydrofluoric Acid (HF)

Hydrofluoric acid (HF, CAS 7664-39-3) is an aqueous solution of hydrogen fluoride and one of the most important fluorine-source chemicals in heavy industry. It is the workhorse reagent wherever silicon dioxide, glass, or metal-oxide scale has to be dissolved and the feedstock from which most commercial fluorochemicals are built. Because HF is uniquely able to attack glass and quartz, no other common acid substitutes for it in etching and microfabrication. It is also extremely hazardous: HF causes severe deep tissue burns, is absorbed through intact skin, and can cause fatal systemic toxicity. This page is written for qualified industrial buyers, EHS, and purchasing teams sourcing bulk material for facilities with the engineering controls, trained personnel, and emergency protocols to handle it. It is not a consumer product.

Typical Properties

Typical reference values, not a specification; the Certificate of Analysis (CoA) for the lot governs.

Industrial applications by sector

Semiconductor and electronics

HF is the standard wet etchant in semiconductor and microelectronics fabrication. It selectively dissolves silicon dioxide while leaving the underlying silicon largely intact, which makes it central to oxide removal, native-oxide stripping, and surface cleaning. Buffered oxide etch (HF buffered with ammonium fluoride) and dilute-HF (DHF) baths are routine. These uses demand electronic / semiconductor-grade material with tightly controlled trace-metal and particle limits, since minor impurities translate directly into device defects.

Metal pickling, cleaning, and stainless passivation

In metal finishing, HF descales and removes oxide and scale from stainless steel and specialty alloys, frequently in a nitric-hydrofluoric pickling mixture. It strips the heat-tint and chromium-depleted layer left by welding and hot working, and supports the cleaning step that precedes passivation, restoring corrosion resistance to the finished surface.

Glass etching and frosting

HF is the only practical acid for etching and frosting glass and quartz. It is used to produce frosted, satin, and decorative surfaces, to mark and number glassware, and for precision polishing in optical and cut-glass work, often in combination with sulfuric acid.

Fluorochemical and fluoropolymer manufacture

HF, and especially anhydrous hydrogen fluoride, is the primary feedstock for the fluorochemical industry. It is the fluorine source for refrigerants and blowing agents (HFCs and their replacements), fluoropolymer monomers, fluorinated specialty chemicals, and inorganic fluorides. It acts both as a fluorinating reagent and as a catalyst in these syntheses.

Aluminum production

HF is consumed in the manufacture of aluminum fluoride and synthetic cryolite, the fluoride feedstocks used in the electrolytic reduction of alumina to aluminum metal.

Oil-well acidizing

In oilfield stimulation, HF is used together with hydrochloric acid as “mud acid” to dissolve silica and clay fines and restore permeability in sandstone formations near the wellbore. The HF component targets the siliceous material that other acids cannot remove.

Refinery alkylation and catalysis

Anhydrous hydrogen fluoride is used as a liquid acid catalyst in HF alkylation units, where it promotes the reaction of isobutane with light olefins to produce high-octane alkylate for gasoline blending. It also serves as a catalyst and fluorinating agent in other petrochemical and synthesis routes.

Grades and forms

HF is supplied in two broad forms. Anhydrous hydrogen fluoride (AHF) is the water-free product, the most reactive form, and the feedstock of choice for fluorochemical synthesis and HF alkylation catalysis. Aqueous hydrofluoric acid is supplied across a range of concentrations to suit the end use — etching, pickling, semiconductor, and acidizing applications each call for different strengths and purities (technical / industrial grade versus high-purity electronic / semiconductor grade). Specify your required concentration, grade, and trace-impurity needs when requesting a quote; the certificate of analysis confirms the assay for the lot you receive. Physical constants such as boiling point and density vary with concentration, so they are referenced to the specific grade rather than to HF in general.

Safety and handling

Hydrofluoric acid is one of the most dangerous industrial chemicals in common use, and the hazard is not proportional to its acid strength. Its GHS classification carries the signal word Danger; depending on concentration it is rated fatal if swallowed, fatal in contact with skin, and fatal if inhaled, and it causes severe skin burns and serious eye damage. Read the SDS before any handling — the points below are an orientation, not a substitute for it, for site EHS, or for medical direction.

• Skin penetration and deep burns. The fluoride ion penetrates intact skin and tissue and continues to cause damage below the surface. Burns from dilute solutions may not be painful or visible immediately, which dangerously delays recognition and treatment.
• Systemic toxicity and hypocalcemia. Absorbed fluoride binds calcium and magnesium in the body, driving down serum calcium (hypocalcemia) and magnesium. This can trigger life-threatening cardiac arrhythmias and cardiovascular collapse. Exposure over even a modest body-surface area, or any inhalation exposure, can be fatal.
• Calcium-based first aid. Industry practice is to keep calcium gluconate (typically a 2.5% gel, with provisions for injectable forms) immediately available at points of use, and to integrate HF exposure into the site emergency-response and occupational-health plan. Specific first-aid and medical treatment must follow the product SDS, facility protocols, and qualified medical professionals — this page does not provide medical advice.
• Engineering controls and PPE. Handle only with the engineering controls (closed transfer, local exhaust ventilation, splash protection) and the specialized acid-resistant PPE specified in the SDS, by personnel trained specifically in HF hazards. Use only HF-compatible materials of construction; HF attacks glass and many metals.

HF is for trained industrial handlers at properly equipped facilities only. RawSource makes no representation that HF is safe to handle, and nothing here qualifies a buyer to handle it — the SDS and your own EHS program govern.

Bulk sourcing from RawSource

RawSource sources hydrofluoric acid in bulk for qualified industrial buyers, in both anhydrous and aqueous grades, matched to your concentration, purity, and packaging requirements. Material is supplied in HF-compatible drums, totes, and bulk packaging to specification. MOQ, lead time, and pricing are quote-based. Request a bulk quote with your target concentration, grade, and volume, and review the SDS before handling.