Ekasilicon

Ekasilicon is the historical name given by Dmitri Mendeleev to a then-unknown element he predicted would lie in the same group as silicon, but with a heavier atomic weight. In his periodic table, he envisioned an element beyond silicon that would behave as a metalloid with chemical properties similar to silicon. The term ekasilicon is best understood as a placeholder label for a future discovery that would complete the analogue of silicon in that portion of the periodic table.

In 1886, German chemist Clemens Winkler identified germanium, whose properties closely matched Mendeleev’s predictions for eka-silicon. Germanium exhibited chemical behavior between those of silicon and tin, and its spectral and atomic characteristics aligned with the anticipated position. The discovery provided a notable validation of the predictive power of the periodic table. The element was named germanium to honor Germany, and the use of the name eka-silicon gradually declined in favor of the official designation.

Today, the term ekasilicon is primarily of historical interest. It appears in discussions of the development of the periodic table and the history of element discovery. Germanium itself is recognized as a metalloid with significant semiconducting properties; its discovery is often cited as a successful example of Mendeleev’s foresight in predicting undiscovered elements.