Pure pentachlorophenol (PCP) consists of light tan to white, needlelike crystals and is relatively volatile. It is soluble in most organic solvents, but practically insoluble in water at the slightly acidic pH generated by its dissociation (pKa 4.7). 1-lowever, its salts, such as sodium pentachloro-phenate (Na-PCP), are readily soluble in water.