Molecular representations of asphaltenes have been proposed from a variety of analytical methods; however, any useful representation must also consider the behavior of these mixtures upon processing. Mild thermal cracking of asphaltenes gives products that have a wide range of boiling points and contain many chemical types, including a range of aromatic, heteroatomic, and aliphatic components. Under severe cracking, the content of aromatic carbon correlates with the yield of solid residue, which can range from 35% to 75%. These process observations are. most consistent with representations of asphaltenes as a variety of aromatic groups joined by bridges and substituted by aliphatic groups.