The complex diberyllocene, CpBeBeCp (Cp = cyclopentadienyl anion), has been the subject of numerous chemical investigations over the past five decades, yet has eluded experimental characterization. Here we report preparation and isolation of the compound by the reduction of beryllocene (BeCp₂) with a dimeric magnesium(I) complex and determination of its structure in the solid state by x-ray crystallography. Diberyllocene acts as a reductant in reactions that form beryllium bonds to aluminum or zinc. Quantum chemical calculations indicate parallels between the electronic structure of diberyllocene and the simple homodiatomic species diberyllium (Be₂).

Structures of known compounds were optimised from crystallographic data. Hypothetical compounds were generated in Avogadro. The geometry optimizations (B3LYP D3BJ def2-TZVP def2/J) were performed with the ORCA (Revision 5.0.3) programme. D3BJ dispersion corrections were used. Full analytical frequency calculations were performed for the optimized structures to ensure the nature of the stationary points found (minima, no imaginary frequencies).