A Fixed-Input Admissibility Rule for Cation Coordination Numbers in Extended Ionic Crystals

This release provides the manuscript, implementation inputs, supporting tables, figures, reproducibility scripts, tests, and validation outputs for “A Fixed-Input Admissibility Rule for Cation Coordination Numbers in Extended Ionic Crystals.” The paper specifies and audits a compact fixed-input admissibility rule for screening cation coordination numbers in extended ionic crystals. The rule uses a provided element-input table, seven fixed structural constants, and a deterministic site-role classifier to assign admissible integer coordination-number sets to structure-determining cation sites. No constant is fitted to the validation data, and no anion-specific admissibility parameter is introduced. The rule is evaluated on 74,050 structure-determining cation sites across 17,947 analyzed structures spanning oxides, fluorides, chlorides, and sulfides. Across all validation datasets, agreement is at least 98.2%. Null, shuffled, Pauling radius-ratio, ablation, per-element, sensitivity, and residual-failure audits are included to separate broad coordination-number prevalence from element-specific discriminative value and to document the remaining failure modes. This repository includes: - LaTeX manuscript source and compiled PDF;- rule implementation inputs and coordination-admissibility logic;- machine-readable supporting-information tables;- generated figures and figure captions;- validation and audit result files;- reproducibility scripts for the reported baselines, ablations, figures, and failure taxonomy;- public test wrappers for the role/API and Division IV role-aware diagnostic checks. Source code is released under the MIT License. The manuscript, figures, tables, results, and non-code documentation are released under CC BY 4.0 unless otherwise noted.