Substance profile
Fluorosulfuric acid
Fluorosulfuric acid is a colorless liquid; reddish-brown color with acetone.
01 · Identification
What Fluorosulfuric acid is
Fluorosulfuric acid is a colorless liquid; reddish-brown color with acetone. Its molecular formula is FHO3S and its molecular weight is 100.07 g/mol. It boils at 163 °C, melts at -89 °C.
Under the GHS it carries the signal word Danger. It is classed as corrosives.
Other names for Fluorosulfuric acid
- fluorosulphonic acid
02 · GHS classification
Hazards and label elements
Harmonised classification under CLP Annex VI. This is the legally binding classification in the EU; other jurisdictions may differ.
| Code | Hazard statement |
|---|---|
| H332 | Harmful if inhaled. |
| H314 | Causes severe skin burns and eye damage. |
Precautionary statements: P260, P271, P280, P301, P304, P310, P312, P331
03 · Physical and chemical properties
Fluorosulfuric acid properties
Every value is shown with the conditions it was measured under and the source it came from. Where sources disagree, all values are listed rather than one being picked — the difference is usually a different form of the substance, not an error.
| Property | Value | Conditions | Source |
|---|---|---|---|
| Boiling point | 163 °C (325.4 °F) | at 760 mmHg | HSDB |
| 162.72 °C (324.9 °F) | at 760 mmHg | CAMEO | |
| 163 °C (325.4 °F) | ICSC | ||
| Melting point | -89 °C (-128.2 °F) | HSDB | |
| -87.28 °C (-125.1 °F) | CAMEO | ||
| Density | 1.7 g/cm³ | ICSC | |
| 1.726 g/cm³ | at 25 °C | HSDB | |
| 1.73 g/cm³ | at 25 °C | CAMEO | |
| Solubility | SOL IN NITROBENZENE | HSDB | |
| Solubility in water: reaction | ICSC | ||
| Vapor pressure | 2.4752 mmHg | at 25 °C | ICSC |
| 2.5 mmHg | Haz-Map | ||
| Vapor density | 3.4 (air = 1) | ICSC | |
| Corrosivity | HIGHLY CORROSIVE | HSDB |
Values compiled from PubChem Laboratory Chemical Safety Summary. Temperatures converted to Fahrenheit for reference.
04 · Handling and storage
Storing and handling Fluorosulfuric acid
Incompatible materials
Reacts violently with water to generate hydrogen fluoride & sulfuric acid mists.
Source: Hazardous Substances Data Bank (HSDB)
Reactivity
FLUOROSULFONIC ACID is very strongly acidic [Merck]. Reacts exothermically with chemical bases (examples: amines, amides, and inorganic hydroxides). These reactions can generate dangerously large amounts of heat in small spaces. Reacts violently with water to generate hydrofluoric acid and sulfuric acid. Reacts with active metals, including such structural metals as aluminum and iron, to release hydrogen, a flammable gas. Can initiate the polymerization of certain alkenes. Reacts with cyanide compounds to release gaseous hydrogen cyanide. Generates flammable and/or toxic gases in contact with dithiocarbamates, isocyanates, mercaptans, nitrides, nitriles, sulfides, and strong reducing agents. Additional gas-generating reactions occur with sulfites, nitrites, thiosulfates (to give H2S and SO3), dithionites (SO2), and carbonates. May catalyze (increase the rate of) chemical reactions.
Source: CAMEO Chemicals
Planning storage for a mix of chemicals? Check Fluorosulfuric acid in the storage compatibility matrix →