Texas Carbon Definition

Can Carbon Form 5 Bonds?

Texas Carbon
Texas carbon refers to carbon atoms with five bonds. Todd Helmenstine

A Texas carbon is the name given to a carbon atom that forms five bonds.

The name Texas carbon comes from the shape formed by five bonds radiating outwards from the carbon similar to the star in the Texas state flag. Another popular idea is that the saying "Everything is bigger in Texas"  applies to carbon atoms.

Although carbon usually forms 4 chemical bonds, it's possible (though rare) for 5 bonds to form.

The carbonium ion and superacid methanium (CH5+) is a gas that can be produced under low-temperature laboratory conditions.

CH4 + H+ → CH5+

Other examples of Texas carbon compounds have been observed.


Synthesis and Characterization of Stable Hypervalent Carbon Compounds (10-C-5) Bearing a 2,6-Bis(p-substituted phenyloxymethyl)benzene Ligand
Kin-ya Akiba et al. J. Am. Chem. Soc.2005127 (16), pp 5893–5901

Planar Pentacoordinate Carbon in CAl5+: A Global Minimum
Yong Pei, Wei An, Keigo Ito, Paul von Ragué Schleyer and Xiao Cheng Zeng J. Am. Chem. Soc.2008 130 (31), 10394-10400