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.
correlation of density and atomic weight. However, the two (or three) different groups shown display little resolution. A more effective way to consider the effect of a cation's atomic weight on mineral density might be to calculate ionic density of the cation. Ionic radius can be used to a spherical ionic volume, and atomic mass divided by that volume to yield ionic density. In the lower plot, mineral density is plotted against ionic density. This plot provides more resolution between the carbonates of monovalent cations