Misapprehending labels as types: A note to the molecular simulation community on kerogen model labeling

In this opinion article, we recall the classification of kerogen into types I through IV using the Van Krevelen diagram. We further discuss the additional subclassification of kerogen into various subtypes based on sulfur content and/or the particular origin of the organic matter. With these foundational definitions kept in mind, we highlight several examples found in the molecular simulation literature wherein individual atomistic models of kerogen have been improperly referred to as representing different “types” or “subtypes” of kerogen. It is argued that, rather than merely being a harmless issue of semantics, such misapprehensions are concerningly detrimental to the molecular simulation community’s understanding of kerogen.