On the terminology of the phenomena of mutual crystal orientation

A system for designation of various types of mutual orientation of crystals and the processes during which they are formed is proposed. The neutral terms oriented overgrowth, oriented intergrowth and oriented inclusions, and in special cases polycrystal and single-crystal films, are considered to be sufficient for describing the fact of regular joint growth. As interpretative and genetic, four basic terms are submitted: epitaxy - for oriented growth of a phase on the crystal surface of another phase; syntaxy - for simultaneous growth of the mutually oriented crystals of two or more phases; topotaxy - for oriented transformation in an open system with a partial alteration in chemical composition of the primary crystal; and endotaxy - for oriented transformation in a closed system, without exchange of components between the system (primary crystal) and its environment. For a later oriented overgrowth of crystals of one and the same phase (in parallel or twin position) it is possible to use the term autoepitaxy.