Ionic order Ionic order The Ionic order forms one of the three classical orders of classical architecture, the other two canonic orders being the Doric and the Corinthian. There are two lesser orders: the Tuscan (a plainer Doric), and the rich variant of Corinthian called the composite order, both added by 16th-century Italian architectural writers, based on Roman practice. Of the three canonic orders, the Ionic order has the narrowest columns. The Ionic capital is characterized by the use of volutes. The Ionic columns normally stand on a base which separates the shaft of the column from the stylobate or platform; the
Electronic band structure structure has been generalised to wavevectors that are complex numbers, resulting in what is called a "complex band structure", which is of interest at surfaces and interfaces. Each model describes some types of solids very well, and others poorly. The nearly free electron model works well for metals, but poorly for non-metals. The tight binding model is extremely accurate for ionic insulators, such as metal halide salts (e.g. NaCl). To understand how band structure changes relative to the Fermi level in real space, a band structure plot is often first simplified in the form of a band diagram. In a