The physical properties of hydrogen fluoride vary with changes in pressure and temperature to an often remarkable extent. This is due to the creation of hydrogen bonds between molecules leading to the formation of short molecular chains (oligomers), the degree of oligomerisation being a function of pressure and temperature.
| Physical Properties |
| Molecular Weight |
20.01 (monomeric) |
| Boiling point |
19.5 °C at 760 mm Hg |
| Specific Gravity |
0.98 at 10 °C |
| Vapour Density (Air = 1) |
2.4 at 20°C |
| Critical Temperature |
187.9°C |
| Critical Pressure |
64.9 bar |
| Critical Density |
290.0 Kg/m³ |
| Heat of Vaporisation at boiling point |
374.5 KJ/Kg |
| Heat of fusion at freezing point |
196.9 KJ/Kg |
Specific heat at constant pressure
Liquid at boiling point Vapour at 25°C, 760 mm Hg |
2.32 KJ/Kg °C
1.46 KJ/Kg °C* |
| Viscosity of liquid at 0°C |
0.25 cP |
| Surface tension at 0°C |
10.27 mN/m |
| Flash point |
Non Flammable |
| Explosive range |
Non Explosive |
| Solubility in water |
Soluble in all ratios |
| Odour threshold |
<1 ppm |
Properties: Heat of Dilution
* Heat evolved when 1 Kg of anhydrous liquid HF at 25 °C is diluted to the given concentration.
Properties: Temperature Variation of Vapour Pressure
Properties: Temperature Variation of Vapour Density
Properties: Temperature Variation of Liquid Density
Properties: Temperature Variation of Density of Superheated Vapour
