Emergent Structural Prototypes 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 6820 distinct structural frameworks, of which 2382 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 6270 materials grouped into 535 frameworks and 327 prototypes, while 5557 ionic compounds occupy 1704 frameworks and 696 prototypes. These results demonstrate that stable inorganic materials naturally coalesce into recurrent structural prototypes and do not require any a priori definition through manual curation. The resulting recurrence-based catalog also 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.