Mineralogical Crystallography: Look in the Past, New Trends, and Highlights

Abstract Many urgent problems of modern mineralogical crystallography, to which the papers of this thematic issue of the journal Kristallografiya (Crystallography Reports) are devoted, have been considered. It is shown how the use of advanced physicochemical methods enriches scientific concepts about the real structures of minerals and nature-like compounds, structural conditionality of their physical properties, forms of concentration of chemical elements in terrestrial shells, crystallogenesis conditions, structural transformations in deep geospheres, relationships between structure types, and their interpretations based on modern concepts. </jats:sec

Iron and its compounds in the earth’s core: new data and ideas

Iron-the most abundant chemical element in the Earth’s core, which it is more than 85% by weight. The remaining ~15% weight of the nucleus is accounted for Ni, and some lighter elements: Si, C, S, O, and H. New data of the transformations of iron and its compounds under the influence of high temperature and pressure, which modeling conditions in the Earth’s core, are analyzed. Structural types of mineralogically possible polymorphic modifications of iron and its compounds in deep geospheres in the Earth’s core are considered. New data about changes in the electronic structure of iron atoms at high pressure are presented. Scientific ideas were expanded and new ideas were put forward about the forms of concentration of chemical elements at ultra-high temperature and pressure. It is concluded that modern views on the specific features and properties of the Earth’s mantle and core are based not only on the results of geological and geophysical methods, but are clarified using micro-mineralogical and crystallographic approaches.</jats:p