Abstract
The discovery of graphene stimulated the intense search for possibilities of other 2D analogs of it. These investigations resulted in many wonder materials, especially from elements of the 14th group of the periodic table. One of the most celebrated 2D structures of the 14th group after graphene is a germanium-based 2D structure known as germanene. Like graphene, germanene is also a single-atom-thick 2D structure. There are several similarities in the structures and properties of graphene and germanene; however, they are distinct in several other properties due to the difference in atomic size, effective nuclear charge, and band structures. One of the most defining phenomena in the structures of graphene and germanene is the buckled structure of the germanene derivative. The buckled structure allows unique orbital mixing and changes the hybridization mode among combining germanium atoms. On the one hand, carbon atoms in graphene exhibit a planer geometry with mesmerizing consistency of the sp2 -hybridized orbitals. On the other hand, germanium atoms tend to exhibit mixed sp2 and sp3 hybridizations. Germanene has gained more popularity due to ease in manipulating its band structure with possibilities to revamp the existing electronics. In addition, mixed hybridization offers the remarkable potential to use this material in various energy and catalytic applications. This chapter deals with various aspects of its chemistry and properties ranging from different methods of synthesis of germanene and its functionalized derivatives, band gap manipulation in these structures, and catalytic applications.