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IONIC - 3 reference results
ionic bond: see chemical bond.
Ionic order, one of the early orders of architecture. The spreading scroll-shaped capital is the distinctive feature of the Ionic order; it was primarily a product of Asia Minor, where early embryonic forms of this capital have been found. In the Ionian colonies of Greece on the southwestern shores of Asia Minor, the Ionic order had attained a full development in the 6th cent. B.C. In the 5th cent. B.C. it appeared in Greece proper, where the Erechtheum embodies the one really complete example. Greek Ionic columns are of slender proportion, their height being generally about nine times the column's lower diameter; the order is always used with a base. A column shaft with 24 flutings seems to have been the most developed form. The spiral scrolls, or volutes, at either side of the cap run from front to rear, and an echinus molding with egg-and-dart ornamentation occupies the space between them. The entablature, usually about one quarter the height of the column, has an architrave generally divided into three bands, each projecting beyond the next; a frieze, often adorned with sculpture; and a cornice enriched with dentils, above which are a corona and a crowning cyma molding. A late and vigorously monumental development of the order took place in the Hellenistic temples of Asia Minor at the middle of the 4th cent. B.C. In employing this order the Romans used details that were not as fine. The temple of Saturn shows a variation of the four-cornered Ionic cap, which had been created in Greece for the corner columns of a portico. A cap of this type, with corner volutes, was developed by the Italian Renaissance architect Scamozzi into a design bearing his name; variations of it were widely used during the Renaissance and in subsequent periods, particularly the baroque. For the other Greek orders see Doric order; Corinthian order.

Electrostatic attraction between oppositely charged ions in a chemical compound. Such a bond forms when one or more electrons are transferred from one neutral atom (typically a metal, which becomes a cation) to another (typically a nonmetallic element or group, which becomes an anion). The two types of ion are held together by electrostatic forces in a solid that does not comprise neutral molecules as such; rather, each ion has neighbours of the opposite charge in an ordered overall crystalline structure. When, for example, crystals of common salt (sodium chloride, NaCl) are dissolved in water, they dissociate (see dissociation) into two kinds of ions in equal numbers, sodium cations (Na+) and chloride anions (Cl). Seealso bonding; covalent bond.

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