Principle of modular crystal structure

The principle of modular crystal structure has been formulated and the possibility of choosing a module of a specified structure type for its subsequent modular design is discussed. The modular characteristics of some structure types based on cubic close packing (fundamental and basic modules and the module that can be used to obtain a certain variety of modular structures related to the initial parent type) are described. Possible ways to obtain such a module and the algorithm for choosing it are considered. A comparative analysis of the theoretically derived module with the modules of experimentally determined modular structures is performed by the example of spinelloids (materials with spinel-like structure).