Zirconyl chloride is probably the most important, stable and water-soluble zirconium compound. Often referred to as ZrOCl2.8H2O its true structure is much more complicated and represented by: [Zr4(OH)8(H2O)16]Cl8(H2O)12.
It should not be confused with anhydrous zirconium tetrachloride - ZrCl4.
It is highly soluble in water but insoluble in conc. HCl.
The compound can be prepared by dissolving freshly prepared zirconium hydroxide - Zr(OH)4 - in strong, hot HCl. The obtained solution is then boiled in, in the presence of plenty acid reserve (to prevent hydrolysis). Alternatively, a solution of zirconyl chloride can be gassed with HCl gas to saturation, upon which pure ZrOCl2.8H2O then crystallises out.
Zirconyl chloride solutions precipitate Zr(OH)4 with ammonia solutions, which can then be dissolved in any relevant acid, after filtering and washing.