Illustrated Glossary of Organic Chemistry

Fused: (1) Two or more rings that share an edge (i.e., the share two bonded atoms).

Naphthalene is a fused bicyclic aromatic molecule. The shared atoms and bond that cause the molecule to be fused are shown in red.

Bicyclo[2.2.1]heptane is a bridged bicyclic molecule.

Spiro[2.3]hexane is a spiro bicyclic molecule.

(2) A substance that has been melted, then allowed to solidify.





Boron trioxide

Soda ash


A Pyrex glass beaker
Borosilicate (Pyrex) glass used in most laboratory glassware is manufactured by fusing silica (SiO2; essentially highly purified sand), boron trioxide (B2O3), soda ash (sodium carbonate; Na2CO3), and lime (calcium oxide; CaO) at high temperature, then allowing this melt to cool and solidify.