Decahydronaphthalene

Decahydronaphthalene (also known as decalin, or as bicyclo[4.4.0]decane), a bicyclic organic compound, is an industrial solvent. A colorless liquid with an aromatic odor, it is used as a solvent for many resins. It is the saturated analog of naphthalene and can be prepared from it by hydrogenation in a fused state in the presence of a catalyst. Decahydronaphthalene easily forms explosive organic peroxides upon storage in the presence of air.

Isomers
Decahydronaphthalene occurs in cis and trans forms. The trans form is energetically more stable because of fewer steric interactions.