Entablature being called petrification. The structure of the entablature varies with the three classical orders: Doric, Ionic, and Corinthian. In each, the proportions of the subdivisions (architrave, frieze, cornice) are defined by the proportions of the column in the order. In Roman and Renaissance interpretations, it is usually approximately a quarter of the height of the column. Variants of entablature that do not fit these models are usually derived from them. Pure classical Doric entablature is simple. The architrave, the lowest band, is split, from bottom to top, into the guttae, the regulae, and the taenia. The frieze is dominated by
Ionic compound for high-temperature solid-state synthesis. Many metals are geologically most abundant as ionic compounds within ores. To obtain the elemental materials, these ores are processed by smelting or electrolysis, in which redox reactions occur (often with a reducing agent such as carbon) such that the metal ions gain electrons to become neutral atoms. According to the nomenclature recommended by IUPAC, ionic compounds are named according to their composition, not their structure. In the most simple case of a binary ionic compound with no possible ambiguity about the charges and thus the stoichiometry, the common name is written using two words. The