Lignin empirical formulal are based on ratios of methoxy groups to phenylpropanoid groups (MeO?:c9). The general empirical formula for lignin monomers is C9H10O2? (OCH3)n, where n is the ratio of MeO? to C9 groups. Where no experimental ratios have been found, they are estimated as follows: 0.94 for softwoods, 1.18 for grasses, 1.4 for hardwoods. These are averages of the lignin ratios found in the literature. Paper products, which are produced primarily from softwoods, are estimated to have an MeO?:C9 ratio of 0.94.

See also: Lignin Ratio