Germanium has a crystalline structure similar to diamond, with each atom bonded to four nearest neighbors in a tetrahedral arrangement. The bonds in germanium are covalent, meaning that they are formed by the sharing of electrons between atoms. In a covalent bond, the electrons are not transferred from one atom to another, but rather are held in common between the atoms. This type of bonding is common in semiconductors, which are materials that have properties that are between those of conductors and insulators.