Dear Colleagues,

Research into crystalline materials based on hydroxyapatite and perovskite materials is rapidly progressing in the field of solid-state science, uniting chemists and experimental and theoretical physicists from all around the world. Our focus is on crystalline solids with structural, electronic, optical, thermoelectric, mechanical properties, etc., which are governed by the migration of ions. Hydroxyapatite materials have primarily gained attention for their applications in bone repair and regeneration in the form of granules, blocks, and scaffolds, either alone or as a composite with polymers or other ceramics, such as for coatings on orthopedic or dental implants. Furthermore, perovskite materials have emerged as the most promising and efficient low-cost energy materials for various optoelectronic and photonic device applications. Although, these materials have been extensively studied in recent years, research into the properties of these materials in their defect states that focuses on robust resources to teach the concepts therein is still in its infancy. For instance, the interplay between ion migration and defect states is still under debate, while the properties of these crystalline materials in their pristine state are well established. Recently, research has shown that the defect states inherent in the bulk of these materials can cause transitions into superconducting states by electron–electron interactions. However, what are the other outcomes of defects? Is it possible to tune the properties of these materials by pressure etc.? Research is still needed to answer these basic questions, making them hot topics. In terms of teaching the concepts of crystallography, there are several crystallographic databases, such as the Cambridge Structural Database (CSD), Materials Project (MP), crystallographic Open Database (COD), etc., that could serve as important resources for teaching crystallographic concepts based on the physical, chemical, and intermolecular interactions of these materials. The present Special Issue on “Hydroxyapatite and Perovskite Materials: Synthesis, Characterization, Atomistic Simulations, and Resources for Teaching the Concepts” is expected to summarize the progress achieved in the last five years.

Dr. David Olubiyi Obada
Guest Editor

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• synthesis
• characterization
• industrial applications
• ab initio calculations
• engineering education
• pedagogy