| IUPAC name
| Other names
|Molar mass||100.06 g/mol|
|Melting point||−87.5 °C (−125.5 °F; 185.7 K)|
|Boiling point||165.4 °C (329.7 °F; 438.5 K)|
|Solubility|| Soluble in glacial acetic acid, ethyl acetate, nitrobenzene|
Poorly soluble in alkanes
|Vapor pressure||2.47 mmHg at 25 °C|
|Safety data sheet||Sigma-Aldrich|
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Fluorosulfuric acid or sulfurofluoridic acid is one of the strongest commercially available acids, more specifically a superacid. It has the chemical formula HFSO3.
Fluorosulfuric is one of the strongest known simple Brønsted acids, although carborane-based acids are still stronger. It has an H0 value of −15.1 compared to −12 for sulfuric acid.
Fluorosulfuric acid reacts with water to release sulfuric acid and hydrofluoric acid.
Fluorosulfuric acid is a colorless liquid that fumes in air and reacts violently with water.
Fluorosulfuric acid is sold by chemical suppliers, though it's not easy to acquire.
- HF + SO3 → HSO3F
- Make magic acid
Fluorosulfuric acid is considered to be highly toxic and corrosive. It hydrolyzes to release HF. Addition of water to this acid is extremely violent, much more that the addition of water to concentrated sulfuric acid.
Fluorosulfuric acid should be kept in thick HDPE or PTFE bottles, in a dry place.
Strongly dilution with cold water, followed by careful neutralization with a base. Products are sulfates and fluorides, which can be dumped in trash.