Doric order proportions. It is suggested that these proportions give the Doric columns a masculine appearance, whereas the more slender Ionic columns appear to represent a more feminine look. This sense of masculinity and femininity was often used to determine which type of column would be used for a particular structure. The most influential, and perhaps the earliest, use of the Doric in Renaissance architecture was in the circular "Tempietto" by Donato Bramante (1502 or later), in the courtyard of San Pietro in Montorio, Rome. Before Greek Revival architecture grew, initially in England, in the 18th century, the Greek or elaborated Roman
Ionic radius Ionic radius Ionic radius, "r", is the radius of an atom's ion in ionic crystals structure. Although neither atoms nor ions have sharp boundaries, they are sometimes treated as if they were hard spheres with radii such that the sum of ionic radii of the cation and anion gives the distance between the ions in a crystal lattice. Ionic radii are typically given in units of either picometers (pm) or angstroms (Å), with 1 Å = 100 pm. Typical values range from 30 pm (0.3 Å) to over 200 pm (2 Å). The concept can be extended to solvated ions