"Dimitri Mendeleev was probably the greatest scientist produced by Russia. ...the periodic table was developed by Mendeleev, as well as five other scientists, over a period of about 10 years, after the Italian chemist Cannizzaro had published a consistent set of atomic weights in 1860. It appears that Mendeleev was unaware of the work of several of his co-discoverers, however. ...What is not well known is that about half of the elements that Mendeleev predicted were never found."