Claus' benzene is a hypothetical hydrocarbon

Hydrocarbon

In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons from which one hydrogen atom has been removed are functional groups, called hydrocarbyls....

 and an isomer

Isomer

In chemistry, isomers are compounds with the same molecular formula but different structural formulas. Isomers do not necessarily share similar properties, unless they also have the same functional groups. There are many different classes of isomers, like stereoisomers, enantiomers, geometrical...

 of benzene

Benzene

Benzene is an organic chemical compound. It is composed of 6 carbon atoms in a ring, with 1 hydrogen atom attached to each carbon atom, with the molecular formula C6H6....

 . It was proposed by Adolf Karl Ludwig Claus

Adolf Karl Ludwig Claus

Adolf Karl Ludwig Claus was a German chemist. He is known for his structure of benzene proposed in 1867.-Life:Claus was born in 1838 in Kassel, Germany. Starting from 1850, he studied medicine in Marburg and later chemistry at the University of Marburg, with Hermann Kolbe...

 in 1867 as a possible structure for benzene at a time when the structure of benzene was debated. The molecule can be described as a hexagon with carbon atoms positioned at the corners, with each carbon connected to its nearest ortho carbon and the two para carbons connected diametrically . High strain energy

Strain energy

In a molecule, strain energy is released when the constituent atoms are allowed to rearrange themselves in a chemical reaction or a change of chemical conformation in a way that:* angle strain,* torsional strain,* ring strain and/or steric strain,...

makes its synthesis impossible.