Elemental crystalline Boron

Facts about Boron:

  • Boron: Metalloid, with a high melting point and an empty P-orbital
  • Fun fact about Boron: One of the key elements in Borax which is used to make slime.
  • Chemical symbol: B
  • Atomic number: 5

A crystal structure containing Boron:

A diborane illustrating the 'Banana bonding' of 2 borons bridged by 2 hydrogens

Facts about this structure:

  • Formula: C58 H58 B2 F18 P2
  • Structure name: bis(μ-hydrido)-bis(2,4,6-tris(trifluoromethyl)phenyl)-bis(2-[bis(2,4,6-trimethylphenyl)phosphanyl]ethyl)-di-boron
  • Fun fact about the structure: This compound is a mild reductant capable of making fomaldehyde from carbon monoxide
  • CSD refcode: DOBDOQ (What's this?)
  • Associated publication: Gerhard Erker, Jun Li, Constantin G. Daniliuc, Gerald Kehr, Angewandte Chemie, International Edition, 2019, 58, 6737, DOI: 10.1002/anie.201901634

More info:

Boron's chemistry is largely governed by it only having 3 electrons in its outer shell. As a result it tends to form 3 covalent bonds leaving one p-orbital unoccupied which can accept lone pairs of electrons. What is unusual in diboranes is that whilst a covalently bound hydrogen has no lone pairs, two molecules containing boron hydrogen bonds can share hydrogens in a form known colloquially as banana bonding due to its shape. This was first proposed by Longuet-Higgins while still an undergraduate chemist at Balliol college Oxford.

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If you want to find out more about some of the terms and concepts we have a Frequently Asked Questions Page.

A visualisation showing the structure containing Boron alongside other structures published in the same scientific article: