Ionic order cap is usually enriched with egg-and-dart. Since Vitruvius, a female character has been ascribed to the Ionic (in contrast to the masculine Doric). The major features of the Ionic order are the volutes of its capital, which have been the subject of much theoretical and practical discourse, based on a brief and obscure passage in Vitruvius. The only tools required to design these features were a straight-edge, a right angle, string (to establish half-lengths) and a compass. Below the volutes, the Ionic column may have a wide collar or banding separating the capital from the fluted shaft (as in, for
Ionic compound and negative ions must be maintained. Instead the material undergoes fracture via cleavage. As the temperature is elevated (usually close to the melting point) a ductile–brittle transition occurs, and plastic flow becomes possible by the motion of dislocations. The compressibility of an ionic compound is strongly determined by its structure, and in particular the coordination number. For example, halides with the caesium chloride structure (coordination number 8) are less compressible than those with the sodium chloride structure (coordination number 6), and less again than those with a coordination number of 4. When ionic compounds dissolve, the individual ions dissociate and