Fluoroantimonic acid
Fluoroantimonic acid is a chemical substance. The acid is a mixture of hydrogen fluoride and Antimony pentafluoride. It is a liquid at 25 degrees Celsius at standard atmosphere (a specific pressure).
This chemical is a superacid that can be more than 10¹⁶ times stronger than pure sulfuric acid, with pH generally dependent on the ratios of hydrogen fluoride and antimony pentafluoride. It is reported to have a pH of -31.3. Extreme care must be taken when handling and storing fluoroantimonic acid; it is more than corrosive enough to dissolve ordinarily corrosion-resistant materials, including glass. It is generally stored in PTFE-coated (commonly known as Teflon) containers, as only the fluoride-carbon bonds in PTFE are strong enough to resist protonation from fluoroantimonic acid.
Properties
Acidity: Fluoroantimonic acid is often rated as around 10^16 times stronger than pure sulfuric acid, giving it one of the highest known acidities.
pH: This acid is so strong that it doesn't have a measurable pH value in the traditional sense, as it readily donates protons in virtually any environment.
Protonation Power: Fluoroantimonic acid can protonate even weak bases and hydrocarbons, which are typically non-reactive to most other acids.
Reactivity: Its extreme reactivity means it can rapidly corrode glass, metals, and most organic materials. It's stored in specialized containers, typically made of Teflon or other highly resistant materials.
Structure and Chemistry
Formation: HSbF₆ is created by mixing HF and SbF₅. The reaction generates an equilibrium of the complex and ions. The proton (H⁺) in this complex is extremely mobile, which accounts for its high acidity.
Solvent Properties: Because of its ionizing power, fluoroantimonic acid is used as a protonating solvent in some highly specialized chemical reactions, especially in research involving carbocations and organic reaction mechanisms.
Uses and Handling
Research Applications: Due to its extreme strength, fluoroantimonic acid is used mainly in laboratory research, especially in organic chemistry and superacid studies, to create highly charged intermediates and study their reactions.
Safety Concerns: This acid is exceptionally dangerous. Direct exposure can lead to severe burns and even respiratory damage due to its fumes. Handling requires strict safety protocols, including the use of specialized protective gear and containment equipment.
Storage and Stability
Storage: HSbF₆ cannot be stored in glass or most metals due to its corrosive nature. Teflon-lined containers are often used because they provide resistance to the acid's corrosive effects.
Instability: The acid decomposes in the presence of moisture, releasing toxic and corrosive gases. It must be handled in dry, controlled environments.
