Mineralogical Crystallography: III. Simple Nonmetallic Substances

The most important structure types of nonmetals belonging to the VIII–IV groups and their importance for the development of the ideas about the composition and structure of the deep shells of the Earth and terrestrial-group planets are analyzed. The structural features of gas hydrates and their possible role in geological processes are considered. The structures of inert gases, hydrogen, and astrophysical ices in the Earth and other planets of the Solar system are presented in the light of new data. The modern concepts of the crystal chemistry of carbon polymorphs, genetic types of diamond, the indicator role of inclusions in its crystals, and conditions of its formation in nature and in model experiments are reviewed.