Beryllium dichloride bonding

Nucleophilic carbene 4 (R = Me, R = H) has been shown to disrupt the polymeric structure of beryllium dichloride to form an ionic carbene complex, 10 (15). The crystal structure of 10 revealed that the cation possesses a distorted tetrahedral coordination geometry at the beryllium center. The average Be-Cl bond distance (2.083(7) A) is... 

They will be orthogonal to each other, and also to the two sp hybrid orbitals. If two atoms were hybridised into the sp configuration, then the remaining p orbitals could be empty as in beryllium dichloride, BeCl2 or alternatively, they could form two 7t bonds, each orthogonal to the other, but... 

A new complex formed between endo-dicyclopentadiene and gold(I) chloride has been prepared by a substitution reaction in dichloromethane, whereby carbon monoxide in dissolved [AuCl(CO)] has been displaced by the endo-dicyclopentadiene ligand/-The first example of the use of the Hofmann/Fischer reagent cyclopentadienylindium(I) for carbon-carbon bond formation and the demonstration of a one-pot tandem addition/intramolecular Diels Alder reaction in aqueous media have been reported/ The synthesis and solid-state structures of two new beryllocenes have been reported. These are [Be(CsMe4H)2] and [Be(C5Mes)2], which are obtained in the metathesis reactions of the potassium salts of the cyclopentadienes with beryllium dichloride, the former at room temperature and the latter at elevated (115 °C) temperature. ... 

Lewis noted that fused beryllium dichloride has a very low electrical conductivity and suggested that the Be-Cl bonds are covalent rather than ionic. This implies that the Be atom has only two electron pairs in the valence shell. 

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