Di-<i>ortho</i>-beryllated Carbodiphosphorane: A Compound with a Metal–Carbon Double Bond to an Element of the s‑Block

Double bonds have been realized for a wide variety of elements in the p-, d-, and f-blocks. However, no s-block metal complexes with a double bond have been identified. Here we report the synthesis and characterization of a di-ortho-beryllated carbodiphosphorane, which exhibits a double dative BeC bond. This species shows an unprecedented bonding situation at the metal center, which was extensively analyzed by experimental and computational means.