SBF

SBF may refer to:

Antimony pentafluoride

Antimony pentafluoride is the inorganic compound with the formula SbF₅. This colourless, viscous liquid is a valuable Lewis acid and a component of the superacid fluoroantimonic acid, the strongest known acid. It is notable for its Lewis acidity and its ability to react with almost all known compounds.

Preparation

Antimony pentafluoride is prepared by the reaction of antimony pentachloride with anhydrous hydrogen fluoride:

It can also be prepared from antimony trifluoride and fluorine.

Structure and chemical reactions

In the gas phase, SbF₅ adopts a trigonal bipyramidal structure of D_3hpoint group symmetry (see picture). The material adopts a more complicated structure in the liquid and solid states. The liquid contains polymers wherein each Sb is octahedral, the structure being described with the formula [SbF₄(μ-F)₂]_n ((μ-F) denotes the fact that fluoride centres bridge two Sb centres). The crystalline material is a tetramer, meaning that it has the formula [SbF₄(μ-F)]₄. The Sb-F bonds are 2.02 Å within the eight-membered Sb₄F₄ ring; the remaining fluoride ligands radiating from the four Sb centers are shorter at 1.82 Å. The related species PF₅ and AsF₅ are monomeric in the solid and liquid states, probably due to the smaller sizes of the central atom, which limits their coordination number. BiF₅ is a polymer.

SBF 250

The SBF 250 (Société des Bourses Françaises 250 Index) is a French stock market index representing all sectors of the French economy. It contains all the component stocks of the SBF 120 Index.

The SBF 250 is calculated twice a day (at opening and at closing). Its base date is December 31, 1990, and its base value is 1,000.

See also

External links