Antimony pentafluoride

Antimony pentafluoride

A colorless, oily liquid with a pungent odor

Liquid

2.99 g · cm -3 ( 20 ° C)

7 ° C

149.5 ° C

13 hPa ( 25 ° C)

Violent reaction with water

Attention

Repealed as carcinogenic

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Antimony pentafluoride is a colorless oil consisting of the elements antimony, and fluorine. It has the chemical formula SbF5.

Production and representation

Antimony pentafluoride is produced by the reaction of antimony (III ) fluoride with fluorine.

Properties

Physical Properties

In the gas phase, the molecules are individually present in trigonal bipyramidal structure. In the liquid phase, however, the antimony pentafluoride is a chain polymer with the formula ( SbF5 ) n (n mostly between 5 and 10) before.

Up to a temperature of 152 ° C is antimony pentafluoride as a trimer to 252 ° C as a dimer, also as a monomer.

In the solid phase of antimony pentafluoride is cyclic tetramers.

Chemical Properties

Antimony pentafluoride is a very strong Lewis acid and a strong F - acceptor. As a result, there are various adducts (eg, SbF5 · SO2, NO2 · SbF 5 ) and complexes ( for example, MF · SbF 5 = M SbF6 - ).

Antimony pentafluoride is able to enhance the oxidation power of fluorine, so that it is able to oxidize oxygen.

Antimony (V ) fluoride attacks glass, behaves towards copper and lead but only slightly corrosive. Quartz, platinum and aluminum are not attacked.

Use

Because of its strong Lewis acidity can be prepared so-called super acids of antimony pentafluoride in combination with strong Brønsted acids. Well known is the "magic acid" (Magic Acid ), which consists of antimony pentafluoride and fluorosulphonic. The most acidic, previously known mixture of the two substances is made fluorosulphonic with 25 mol % of antimony pentafluoride and reaches a value of H0 -21.5. Thus, it is around 1010 times stronger than pure sulfuric acid. It is to decompose able paraffins and to protonate very weak bases, such as CH4 CH5 to. Similarly, this can fluorine - antimony acid, a mixture of antimony pentafluoride and hydrogen fluoride in the ratio 1:1. She has an H0 value of -31.3 and is therefore approximately 2 × 1019 times stronger than pure sulfuric acid.

Safety

Due to the high reactivity of antimony pentafluoride should be handled very carefully. Unintentional contact with other substances, particularly with moisture should be avoided in any case. As products of decomposition of hydrogen fluoride and stibane may arise.

The LD50 ( mouse inhalation) is 270 mg/m3.