General
Name	Hydrogen fluoride
Chemical formula	HF
Appearance	Colorless gas
Physical properties
Formula weight	20.1 amu
Melting point	190 K (-83 °C)
Boiling point	294 K (19.5 °C)
Density	0.97 ×103 kg/m3 (liquid)
Solubility	miscible with water
Thermochemistry
ΔfH0gas	? kJ/mol
ΔfH0liquid	? kJ/mol
ΔfH0solid	? kJ/mol
S0gas, 1 bar	? J/mol·K
S0liquid, 1 bar	? J/mol·K
S0solid	? J/mol·K
Safety
Ingestion	Toxic, most likely fatal.
Inhalation	Highly toxic, most likely fatal, non-fatal doses can result in pulmonary edema.
Skin	Most likely fatal, absorbs through skin to cause nerve, bone and organ damage.
Eyes	Extremely dangerous, high chance of blindness.
SI units were used where possible. Unless otherwise stated, standard conditions were used. Disclaimer and references

Hydrofluoric acid is a highly corrosive solution of the chemical compound hydrogen fluoride in water. Pure hydrogen fluoride is often called anhydrous hydrofluoric acid. Paradoxically, though in chemical terms hydrofluoric acid is a weak acid, it has the unique ability to dissolve almost all inorganic oxides. As such, it must be stored in plastic containers, though ideally it should be stored in teflon bottles. In the human body, hydrofluoric acid reacts with calcium and damages nerves, bone, and several organs including the heart and kidneys.

Initial treatment to hydrofluoric acid exposure usually involves applying calcium gluconate gel to the exposed areas. If exposure is high, or too much time has passed, a calcium solution may be injected directly into a local artery or surrounding tissues. In all cases, hydrofluoric acid exposure requires immediate professional medical attention.

Production

Industrially, hydrofluoric acid is produced from the mineral fluorspar, also known as calcium fluoride (chemical formula CaF₂) and concentrated sulfuric acid. When combined at 250°C, these two substances react to produce hydrogen fluoride according to the chemical equation

CaF₂ + H₂SO₄ → 2 HF + CaSO₄

The vapors from this reaction are a mixture of hydrogen fluoride, sulfuric acid, and a few minor byproducts, from which hydrogen fluoride can be isolated by distillation.

Uses

Hydrofluoric acid's ability to dissolve oxides makes it important in the purification of both aluminium and uranium. It is also used to etch glass, to remove surface oxides from silicon in the semiconductor industry, as a catalyst for the alkylation of iso-butane and butene in oil refineries and to remove oxide impurities from stainless steel in a process called pickling.

Hydrofluoric acid is also used in the synthesis of many fluorine-containing organic compounds, including teflon and refrigerants such as freon.

Safety

In the body, hydrofluoric acid reacts with calcium and magnesium ions and can disable organs whose proper function depends on these metal ions. Exposure to hydrofluoric acid may not be initially painful, and symptoms may not occur until several hours later, when the acid begins to react with calcium in the bones. If left untreated, hydrofluoric acid exposure can result in severe or even lethal damage to the heart, liver, kidneys, and nerves.

Exposure of less than 10% of the body can be fatal, even with immediate medical treatment. [1] http://www.safetyline.wa.gov.au/pagebin/pg001383.htm