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.
The oppositely charged ions â typically a great many of them â are then attracted to each other to form a solid. Ionic bonding is a type of chemical bond that involves the electrostatic attraction between oppositely charged ions, and is the primary interaction occurring in ionic compounds. The ions are atoms that have gained one or more electrons (known as anions, which are negatively charged) and atoms that have lost one or more electrons (known as cations, which are positively charged).