A nontoxic substitute for hazardous heavy liquids—aqueous sodium polytungstate (3Na2WO4.9WO3.H2O) solution (Note)

Abstract
Aqueous solutions of the salt sodium polytungstate can be prepared with varying densities up to 3.1 g/cm3. The salt is nontoxic and it is recommended as a substitute for the hazardous halogenated hydrocarbons, tetrabromoethane and bromoform, customarily used in geological laboratories to perform light/heavy mineral separations.