Zirconium perchlorate as cold as possible. Zirconium perchlorate is very hydroscopic forming hydrates, and it is hydrolysed by water to yield zirconyl perchlorate, ZrO(ClO). Zirconium perchlorate reacts with vaseline, methyl nitrate or acetonitrile. Zirconium perchlorate is inert towards carbon tetrachloride, chloroform, and dimethylformamide. Zirconium perchlorate reacts with benzene at 20°C, but at -10°C crystals of Zr(ClO)•CH are deposited. Zirconium perchlorate has solid state transition around 45°C, a melting point between 95.5 and 96.0°C and a decomposition point starting around 120°C. The zirconyl perchlorate formed in the heat decomposition, itself decomposes around 290°C to form zirconia, chlorine and oxygen. In the gas phase
Group 4 element zirconium in the mineral zircon in 1789 and named it after the already known Zirkonerde (zirconia). Hafnium had been predicted by Dmitri Mendeleev in 1869 and Henry Moseley measured in 1914 the effective nuclear charge by X-ray spectroscopy to be 72, placing it between the already known elements lutetium and tantalum. Dirk Coster and Georg von Hevesy were the first to search for the new element in zirconium ores. Hafnium was discovered by the two in 1923 in Copenhagen, Denmark, validating the original 1869 prediction of Mendeleev. There has been some controversy surrounding the discovery of hafnium and the extent