Reported in EPA TSCA Inventory.

OSHA PEL: TWA 2.5 mg(F)/m³
ACGIH TLV: TWA 2.5 mg(F)/m³; BEI: 3 mg/g creatinine of fluorides in urine prior to shift; 10 mg/g creatinine of fluorides in urine at end of shift.
NIOSH REL: (Inorganic Fluorides) TWA 2.5 mg(F)/m³
DOT Classification:  8; Label: Corrosive

The Fluosulfuric acid, with the CAS registry number 7789-21-1 and EINECS registry number 232-149-4, has the systematic name of sulfurofluoridic acid. And the molecular formula of this chemical is FHO₃S. It is a kind of orange crystalline solid, and belongs to the product category of Pharmaceutical Intermediates. It is one of the strongest acids commercially available and is a superacid. What's more, it should be stored at 2-8°C.

The physical properties of Fluosulfuric acid are as following: (1)ACD/LogP: -0.16; (2)# of Rule of 5 Violations: 0; (3)ACD/LogD (pH 5.5): -3.66; (4)ACD/LogD (pH 7.4): -3.66; (5)ACD/BCF (pH 5.5): 1; (6)ACD/BCF (pH 7.4): 1; (7)#H bond acceptors: 3; (8)#H bond donors: 1; (9)#Freely Rotating Bonds: 0; (10)Polar Surface Area: 51.75 Å²; (11)Index of Refraction: 1.392 ; (12) Molar Refractivity: 12.5 cm³; (13)Molar Volume: 52.5 cm³; (14)Polarizability: 4.95×10^-24cm³; (15)Surface Tension: 52.8 dyne/cm; (16)Density: 1.905 g/cm³; (17)Enthalpy of Vaporization: 44.33 kJ/mol; (18)Boiling Point: 165.5 °C at 760 mmHg; (19)Vapour Pressure: 0.942 mmHg at 25°C.

Preparation of Fluosulfuric acid: It can be prepared by the reaction of HF and sulfur trioxide: SO₃ + HF → FSO₃H

Uses of Fluosulfuric acid: It is useful for regenerating mixtures of HF and H₂SO₄ for etching lead glass. Fluosulfuric acid isomerizes alkanes and the alkylation of hydrocarbons with alkenes, although it is unclear if such applications are of commercial importance. It can also be used as a laboratory fluorinating agent.

You should be cautious while dealing with this chemical. It is harmful by inhalation, and may cause severe burns. Therefore, you had better take the following instructions: In case of contact with eyes, rinse immediately with plenty of water and seek medical advice; In case of accident or if you feel unwell, seek medical advice immediately (show label where possible).

You can still convert the following datas into molecular structure:
(1)SMILES: FS(=O)(=O)O
(2)InChI: InChI=1/FHO3S/c1-5(2,3)4/h(H,2,3,4)
(3)InChIKey: UQSQSQZYBQSBJZ-UHFFFAOYAW