Theoretical and Synthetic Study on the Existence, Structures, and Bonding of the Halide-Bridged [B2X7](-) (X = F, Cl, Br, I) Anions.

While hydrogen bridging is very common in boron chemistry, halogen bridging is rather rare. The simplest halogen-bridged boron compounds are the [B2X7](-) anions (X = F, Cl, Br, I), of which only [B2F7](-) has been reported to exist experimentally. In this paper a detailed theoretical and synthetic study on the [B2X7](-) anions is presented.

A second polymorph of bis-(triphenyl-λ(5)-phosphanyl-idene)ammonium chloride-boric acid adduct.

The title crystal structure is a new triclinic polymorph of [(Ph3P)2N]Cl·(B(OH)3) or C36H30NP2 (+)·Cl(-)·BH3O3. The crystal structure of the ortho-rhom-bic polymorph was reported by [Andrews et al. (1983 ▶).