Boranes: The Boron Subhydride B104.67H3 with a Distorted β-Boron Crystal Structure.

A single crystal of the boron subhydride B104.67(4)H3 was serendipitously obtained while attempting to synthesize β-boron. An accurate crystal structure analysis revealed a distorted β-boron framework with the noncentrosymmetric space group R3m. We have found one interstitial site occupied by boron. The site related by inversion remains empty. The distortions of the framework result in ideal environments for the interstitial boron atom, and for the three hydrogen atoms at bridging positions between icosahedral B12 groups, they result in ideal B-H distances of 1.33 Å. B104.67(4)H3 is a borane with the lowest amount of hydrogen recorded to date, and it is the first compound with a noncentrosymmetrically distorted β-boron framework.