Stability of inorganic ionic structures: the uniformity approach.

Area of Science:

• Solid-state chemistry
• Crystallography
• Materials science

Background:

• Understanding the uniformity of ionic crystal structures is crucial for predicting material properties and stability.
• Existing methods for assessing structural uniformity can be complex and may not fully capture ionic sublattice behavior.

Purpose of the Study:

• To develop and apply a numerical criterion for estimating crystal structure uniformity.
• To investigate the uniformity of ionic sublattices across a large dataset of inorganic ionic compounds.
• To propose new criteria for evaluating the stability of ionic crystal structures based on uniformity.

Main Methods:

• Numerical estimation of crystal structure uniformity using the standard deviation of the crystal space quantizer (G3).
• Application of the G3 criterion to analyze 21,465 crystal structures of inorganic ionic compounds.
• Classification of structures based on G3 values to identify uniform and non-uniform sublattices.

Main Results:

• A significant majority of analyzed inorganic ionic compounds exhibited high sublattice uniformity (small G3 values).
• At least one sublattice (overall, cationic, or anionic) was found to be highly uniform in most structures.
• Non-uniform structures were often identified as potentially erroneous or not purely ionic.

Conclusions:

• The crystal space quantizer (G3) provides an effective measure for assessing ionic sublattice uniformity.
• High sublattice uniformity is a common characteristic of stable inorganic ionic compounds.
• Proposed uniformity criteria can aid in the reliable estimation of ionic crystal structure stability and identification of structural anomalies.