Key information
Atomic number: 
Atomic weight: 
5320 kg/m³
Boiling point: 
3103.16° K
Melting point: 
1210.56° K
Heat vapour: 
284.76 kJ/mol
Heat fusion: 
31.83 kJ/mol
Thermal conductivity: 
2.2 W/m/K
Specific heat capacity: 
58.63 J/kg/K

Mendeleev was able to predict the existence of a number of elements within gaps in the periodic table. Mendeleev predicted the existence of an element "Eka-silicon" in the position germanium would eventually fill. Thus although germanium was, at the time, yet to be isolated he had predicted its existence.Germanium has four valence electrons and forms crystal lattices in which substituted atoms (dopants) can dramatically change the electrical properties.

Electron Shell: 
Amazon Books
Image of The Last Sorcerers: The Path from Alchemy to the Periodic Table
Author: National Academy of Sciences, Richard Morris
Publisher: Henry (Joseph) Press (2003)
Binding: Hardcover, 294 pages