Potassium tetraphenylborate is the salt with the formula KB(C₆H₅)₄). It is a colourless salt that is a rare example of a water-insoluble salt of

potassium Potassium is the chemical element with the symbol K (from Neo-Latin ''kalium'') and atomic number19. Potassium is a silvery-white metal that is soft enough to be cut with a knife with little force. Potassium metal reacts rapidly with atmosph ...

. The salt has a low solubility in water of only 1.8×10⁻⁴ g/L. It is, however, soluble in

organic solvent A solvent (s) (from the Latin '' solvō'', "loosen, untie, solve") is a substance that dissolves a solute, resulting in a solution. A solvent is usually a liquid but can also be a solid, a gas, or a supercritical fluid. Water is a solvent for ...

s. The insolubility of this compound has been used to determine the concentration of potassium ions by

precipitation In meteorology, precipitation is any product of the condensation of atmospheric water vapor that falls under gravitational pull from clouds. The main forms of precipitation include drizzle, rain, sleet, snow, ice pellets, graupel and hail. ...

and

gravimetric analysis Gravimetric analysis describes a set of methods used in analytical chemistry for the quantitative determination of an analyte (the ion being analyzed) based on its mass. The principle of this type of analysis is that once an ion's mass has been ...

: : K⁺ + NaB(Ph)₄ → KB(Ph)₄ + Na⁺ The compound adopts a polymeric structure with bonds between the phenyl rings and potassium. As such it is classified as an

organopotassium compound Organosodium chemistry is the chemistry of organometallic compounds containing a carbon to sodium chemical bond. The application of organosodium compounds in chemistry is limited in part due to competition from organolithium compounds, which are ...

.Ulrich Behrens, Frank Hoffmann, and Falk Olbrich "Solid-State Structures of Base-Free Lithium and Sodium Tetraphenylborates at Room and Low Temperature: Comparison with the Higher Homologues MB(C₆H₅)₄ (M = K, Rb, Cs)" Organometallics 2012, volume 31, p. 905−913.

References

External links

Potassium tetraphenylborate Jmol Page
Potassium compounds Tetraphenylborates {{organic-compound-stub