Xylylene
Xylylene comprises two isomeric organic compounds with the formula C6H4(CH2)2. These compounds are related to the corresponding quinones by replacement of the oxygen atoms by CH2 groups. ortho- and para-xylylene are best known, although neither is stable in solid or liquid form. Certain substituted derivatives of xylylenes are however highly stable, an example being tetracyanoquinodimethane.