Princeton's WordNet(0.00 / 0 votes)Rate this definition: geological time, geologic time(noun) the time of the physical formation and development of the earth (especially prior to human history)
Ionic radius, r ion, is the radius of an atom's ion.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.herefore, the distance between the Na + and Cl â ions is half of 564.02 pm, which is 282.01 pm. However, although X-ray crystallography gives the distance between ions, it doesn't indicate where the boundary is between those ions, so it doesn't directly give ionic radii.
An ionic bond is a bond between ions with opposite charges. Cations (positively charged ions) cannot exist without anions (negatively charged ions). An electron released by an atom to from a cation must be accepted by another atom to form an anion. Cations and anions are formed in many chemical reactions by the transfer of one or more electrons from one element to another. Ionic bonds are formed by a strong attraction between positive and negative ions. Characteristics of Ionic compounds. Some important characteristics of ionic compounds are as follows. 1. Ionic compounds are hard and rigid due to strong forces of attraction between the oppositely charged ions.