Fluoroantimonic acid

Synonym(s):Fluoroantimonic acid;Hexafluoroantimonic acid;Hexafluorostibonic acid;Monohydrogen hexafluoroantimonate

CAS NO.：16950-06-4
Empirical Formula: F6HSb
Molecular Weight: 236.76
MDL number: MFCD00011327
EINECS: 241-023-8
SAFETY DATA SHEET (SDS)
Update Date: 2026-05-28 01:23:22

What is Fluoroantimonic acid?

Description

Fluoroantimonic acid (HSbF6), the strongest known superacid, is made by combining HF with SbF5. It can be as much as 2 × 1019?times stronger than 100% H2SO4. However, superacids are all equally strong in aqueous solution; other solvents must be used to observe their effects.

Chemical properties

superacid; moisture sensitive [KIR78] [ALD94]
Strongest superacid known
mixture of HF and SbF5 (1:1 is strongest)
Protonate even hydrocarbons to afford carbocations and H2.
2×1019 (20 quintillion) times stronger than 100% sulfuric acid.
Ho values of -31.3

The Uses of Fluoroantimonic acid

Hydrogen hexafluoroantimonate(V) is an excellent medium for the preparation of alkylidene oxonium salts.

Preparation

Fluoroantimonic acid is produced by reacting hydrogen fluoride (HF) with antimony pentafluoride (SbF5).
SbF5+HF→SbF6+HF

General Description

HF/SbF₅ may be synthesized by mixing hydrogen fluoride and antimony fluoride.1 Fluoroantimonic acid (HF/SbF₅), is a combination of SbF₅ and HF. It is the known strongest liquid superacid.

Properties of Fluoroantimonic acid

Melting point:	20°C
Density	2.885 g/mL at 25 °C(lit.)
vapor pressure	14 mm Hg ( 18 °C)
form	liquid
color	yellow to colorless
Water Solubility	It is fully miscible with water, soluble in SO2ClF, SO2.
Exposure limits	ACGIH: TWA 0.5 mg/m3 NIOSH: IDLH 50 mg/m3; TWA 0.5 mg/m3
CAS DataBase Reference	16950-06-4(CAS DataBase Reference)
EPA Substance Registry System	Antimonate(1-), hexafluoro-, hydrogen, (OC-6-11)- (16950-06-4)

Safety information for Fluoroantimonic acid

Signal word	Danger
Pictogram(s)	Corrosion Corrosives GHS05 Skull and Crossbones Acute Toxicity GHS06 Environment GHS09
GHS Hazard Statements	H314:Skin corrosion/irritation H411:Hazardous to the aquatic environment, long-term hazard
Precautionary Statement Codes	P260:Do not breathe dust/fume/gas/mist/vapours/spray. P273:Avoid release to the environment. P280:Wear protective gloves/protective clothing/eye protection/face protection. P303+P361+P353:IF ON SKIN (or hair): Remove/Take off Immediately all contaminated clothing. Rinse SKIN with water/shower. P305+P351+P338:IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continuerinsing.