Zirconium Oxychlorides

Although zirconium chloride dissolves in water, hydrolysis takes place, the solution becomes acid, and the oxychloride, ZrOCl₂, is formed in solution; whilst a solution of zirconium hydroxide in hydrochloric acid deposits on evaporation tetragonal crystals of ZrOCl₂.8H₂O. When this compound is heated to 100° C. in a stream of hydrogen chloride ZrOCl₂.3H₂O is formed, and when it is recrystallised from concentrated hydrochloric acid ZrOCl₂.6H₂O separates. According to Chauvenet ZrOCl₂ forms hydrates with 2, 3.5, 6, and 8 H₂O. The oxychloride Zr₂OCl₆ is formed when the tetrachloride is heated in a current of oxygen, and Zr₂O₃Cl₂ when an alcoholic solution of ZrOCl₂ is precipitated with ether. Chauvenet, however, maintains that the only oxychloride besides ZrOCl₂ is Zr₂O₃Cl₂, which exists in the anhydrous and mono- and tri-hydrated forms. When a solution of zirconium oxychloride is dialysed colloidal zirconium hydroxide results.