text: Organoberyllium chemistry is limited to academic research due to the cost and toxicity of beryllium.
  Organoberyllium compounds consist of a beryllium atom with an organic group attached. There are very few reported case of Be(I) and Be(0) oxidation states. Instead, Be has a +2 oxidation state, and higher charge density than any other group 2 element. Organometallic beryllium compounds are highly reactive strong acids. Beryllium has a high electronegativity compare to other group 2 elements; thus the resulting C-Be bonds are less highly polarized than other C-M bonds, although the attached carbon still bears a negative dipole moment.
  Lighter organoberyllium compounds are often considered covalent, but with some ionic bond characteristics. From this perspective, the C-Be bonds are much more ionic and highly polarized than other C-R bonds. This higher ionic character and bond polarization tends to produce high coordination numbers. Many compounds, particularly dialklys, are polymeric in solid or liquid states with highly complex structures in solution; in the gaseous state, they often revert to monomers. A good example is beryllium borohydride, which dimerizes to form three-center two-electron bonds.
  Compounds such as these hydrides can coordinate with carbenes such as N-heterocyclic carbene to form crystals. The propensity for co-crystallization suggests applications in organocatalysis.