Quinacridone

Quinacridone is a red powder. It is an organic compound with the molecular formula C₂₀H₁₂N₂O₂. It is used as a pigment; analogs bearing this motif are known as quinacridones.

Quinacridones

Quinacridones are a family of synthetic pigments used to make high performance paints. Quinacridones are considered "high performance" pigments because they have exceptional color and weather fastness. Major uses for quinacridones include automobile coatings as well as other industrial coatings. They can also be used in artist's paints, including oils, acrylics, and watercolors.

Typically deep red to violet in color, the hue of quinacridone is affected not only by the R-groups on the molecule but by the crystal form of the solid. For example, the γ crystal modification of unsubstituted quinacridone provides a strong red shade that has excellent color fastness and resistance to solvation. Another important modification is the β phase which provides a maroon shade that is also more weather resistant and light-fast. Both crystal modifications are more thermodynamically stable than the α crystal phase.

Basic modifications to the chemical structure of quinacridones include the addition of CH₃ and Cl substituents.

Some magenta shades of quinacridone are labeled under the proprietary name "Thio Violet" and "Acra Violet".

Semiconductor

Quinacridone can form a self-assembling, supramolecular organic semiconductor. The following image, taken by a scanning tunneling microscope, shows these self-assembled quinacridone chains on a graphite background.