text: Organoberyllium chemistry involves the synthesis and properties of organometallic compounds featuring the group 2 alkaline earth metal beryllium (Be). The area remains understudied, relative to the chemistry of other main-group elements, because although metallic beryllium is relatively unreactive, its dust causes berylliosis and compounds are toxic. Organoberyllium compounds are typically prepared by transmetallation or alkylation of beryllium chloride.
  The beryllium functional group in organoberyllium compounds usually serves to coordinate other elements and ligands. Beryllium, one of the smallest atoms on the periodic table, almost always exhibits a +2 oxidation state. The  cation is characterized by the highest known charge density (Z/r = 6.45), making it one of the hardest cations and a very strong Lewis acid.
  Coordination in beryllium can range from a coordination number of two to four. Most common ligands attached to beryllium are halides, hydride (like beryllium borohydride in a three-center two-electron bond), methyl, aryl, and alkyl. Beryllium can form complexes with known organic compounds such as phosphines, N-hetereocyclic carbenes (NHC), cyclic alkyl amino carbenes (CAAC), and β-diketiminates (NacNac).