Volumetric measure of isostructurality.

Area of Science:

• Crystallography
• Materials Science
• Computational Chemistry

Background:

• Existing numerical descriptors for isostructurality have limitations.
• Quantifying structural similarity is crucial in various scientific fields.

Purpose of the Study:

• To critically review existing isostructurality descriptors.
• To propose and validate a novel volumetric measure for isostructurality.
• To develop a numerical approach for calculating this new index, applicable to disordered structures.

Main Methods:

• Definition of a new volumetric isostructurality index based on molecular overlap percentage.
• Development of a numerical method for calculating the index.
• Application of the index to analyze homologous 9-alkylthiophenanthrenes.
• Analysis of structural changes in inclusion compounds (5-methoxysulfadiazine with solvents).
• Characterization of relationships in cocrystallized helical tubuland diols and phenols.

Main Results:

• The proposed volumetric measure effectively quantifies isostructurality.
• The numerical approach successfully handles both ordered and disordered crystal structures.
• The descriptor accurately illustrates structural variations in diverse molecular systems.
• Correlations were established between calculated isostructurality and observed structural modifications.

Conclusions:

• The new volumetric isostructurality index offers a robust and versatile tool for structural analysis.
• This descriptor provides valuable insights into molecular and crystal structure modifications.
• The method is applicable across a range of chemical systems, from simple homologous series to complex inclusion compounds and cocrystals.