Slowly mix 20 g of pyridinium hexachloroplumbate (IV) over the course of 10 minutes with 600 g of conc. sulfuric acid cooled to -10°C. After which let the mixture to stand until layers form. Decant the bottom yellow lead tetrachloride layer into very cold sulfuric acid. Store the product in sulfuric acid at -80°C in an amber bottle.
Decanting the lead tetrachloride into sulfuric acid
The lead tetrachloride under sulfuric acid