Thus, the symbols for californium and einsteinium are Cf and Es. Subsequent separation procedures reduced the amount of isotopically pure einsteinium roughly tenfold. Like all actinides, einsteinium is rather reactive. When preparing einsteinium complexes, the Es ions were 1000 times diluted with Gd ions. Einsteinium is a synthetic element with the symbol Es and atomic number 99. Einsteinium is a soft, silvery, paramagnetic metal. Einsteinium is a synthetic, silvery-white, radioactive metal. Using available microgram quantities of einsteinium, femtogram quantities of mendelevium-256 may be produced. The longest-lived isotope of einsteinium has a half-life of only 472 days. Magnetic properties have been studied for einsteinium metal, its oxide and fluoride. The Berkeley team also reported some results on the chemical properties of einsteinium and fermium. Separation procedure of einsteinium depends on the synthesis method. These processes may contribute to the relatively low density and melting point of einsteinium. Einsteinium (Es) is a synthetic element, and thus a standard atomic weight cannot be given. Known oxyhalides of einsteinium include EsOCl, EsOBr and EsOI.