[Symmetry in perovskite variants]

Area of Science:

• Crystallography
• Materials Science
• Solid-State Chemistry

Context:

• Perovskite structures exhibit a vast array of derivative forms.
• Understanding these relationships is crucial for materials design and prediction.
• Existing classification methods can be complex and fragmented.

Purpose:

• To rationalize the relationships among perovskite derivative structures using group-subgroup theory.
• To provide a systematic framework for understanding symmetry reductions in perovskite modifications.
• To explore the impact of distortions and substitutions on perovskite symmetry.

Summary:

• This study employs group-subgroup relations between space groups to classify perovskite derivative structures.
• It details family trees for tilted octahedra and discusses distortions like Jahn-Teller effects and atomic shifts.
• The framework addresses substitutions (e.g., elpasolites), molecular group occupation, and anion replacements, considering symmetry implications.

Impact:

• Enables prediction of twinning and phase transitions (including second-order) in perovskite materials.
• Provides a unified approach to understanding complex perovskite structures and their symmetries.
• Facilitates the rational design of novel perovskite-based materials with desired properties.