Clemens Alexander Winkler was a German chemist who discovered the element germanium in 1886, solidifying Dmitri Mendeleev's theory of periodicity.

Germanium is a chemical element; it has symbol Ge and atomic number 32. It is lustrous, hard-brittle, grayish-white and similar in appearance to silicon. It is a metalloid in the carbon group that is chemically similar to its group neighbors silicon and tin. Like silicon, germanium naturally reacts and forms complexes with oxygen in nature.