Potassium tetraphenylborate
Potassium tetraphenylborate is the salt with the formula KB. It is a colourless salt that is a rare example of a water-insoluble salt of potassium.
The salt has a low solubility in water of only 1.8×10−4 g/L. It is, however, soluble in organic solvents. The insolubility of this compound has been used to determine the concentration of potassium ions by precipitation and gravimetric analysis:
The compound adopts a polymeric structure with bonds between the phenyl rings and potassium. As such it is classified as an organopotassium compound.
