Our knowledge of the mechanical behavior of 2D solids lags far behind the information available on their electronic properties, despite their relevance for any technological application. A chemistry-based reference model is introduced that allows the unknown mechanical properties to be estimated from a limited data base for groups of atomic and molecular monolayers with similar bonding configuration. This nanometrological approach is demonstrated for the well-studied graphene-like monolayers boronitrene and phosphorene, and the group IV-A monolayers graphene, silicene, germanene, and stanene with hexagonal structure. Comparable results were obtained for the less studied group VI-B molecular layers WS2, MoS2, WSe2, MoSe2, WTe2, and MoTe2. With the ratios of a known property of the group members to that of the reference compound, unknown fracture properties were extracted using a prototype for calibration of this property. The reference model yields very good agreement with existing data for the graphene-like monolayers. For the transition metal dichalcogenides (TMDs) results are still needed for a detailed comparison. The model can be applied to any group of atomic- and molecular layers with a related bonding configuration and stoichiometry. In view of the fast-growing family of 2D solids, the chemical reference model will provide a versatile tool to estimate unknown fracture properties from a minimal data base.
