If it contains nitrogen, then repeatedly concentrate a conc HCl solution until free from nitrogen, and dry free from HCl in a vacuum over CaO until crystals are formed. The olive-green solid (yellow at ~700o) is very hygroscopic. [Woo & Yost J Am Chem Soc 53 884 1931, Grube in Handbook of Preparative Inorganic Chemistry (Ed. Brauer) Academic Press Vol II p1592 1965.]
IRIDIUM(IV) CHLORIDE Preparation Products And Raw materials