Electron deficiency binding
Electron deficiency bonds are chemical bonds in which the atoms have fewer electrons in the valence shell than would be necessary to fill the shell. For the elements of the main groups (with the exception of hydrogen ), this means that these bonds do not meet the octet rule , i.e. the atoms do not have eight electrons in the valence shell.
Chemical compounds with electron deficiency bonds are also often referred to as electron deficiency compounds ; However, this term is misleading because it is also used for electrophilic molecules , i.e. Lewis acids .
Examples of electron deficiency bonds are many hydrides , for example AlH 3 or diborane with a total of only six or twelve valence electrons per formula unit . The bonds in such substances can also be understood as 3-center-2-electron bonds ; the bonding orbitals thus contain three (instead of two) atoms; In other words, three (instead of two) atoms share the electron pairs .
Electron deficiency bonds are not very stable; the compounds formed in this way are therefore reactive.
literature
- Hans Peter Latscha, Martin Mutz: Chemistry of the elements . Springer, Berlin, Heidelberg 2011, ISBN 978-3-642-16914-4 .
- HC Longuet-Higgins: The structures of electron-deficient molecules. In: Quarterly Reviews, Chemical Society. 11, 1957, pp. 121-133, doi : 10.1039 / QR9571100121 .