The Recurrent Structural Frameworks of Stable Inorganic Materials

Abstract

The number of possible crystal structures vastly exceeds the number realized among thermodynamically stable inorganic materials, suggesting that experimentally accessible structure space is organized around a limited set of preferred structural frameworks. Analysis of 23,160 structures on the thermodynamic convex hull identifies 6,820 distinct structural frameworks, of which 2,382 recur across multiple chemically distinct materials and are therefore classified as structural prototypes. Within a filtered dataset, metallic systems exhibit particularly strong structural recurrence, with 6,270 materials grouped into 535 frameworks and 327 prototypes, while 5,557 ionic compounds occupy 1,704 frameworks and 696 prototypes. These results demonstrate that stable inorganic materials occupy a highly compressible region of structure space and establish a recurrence-based catalog of structural prototypes that provides an empirical measure of framework prevalence, enabling the relative likelihood of structural frameworks in future materials to be estimated from their recurrence among known compounds.