Grimm's Hydride Displacement Law is an early hypothesis to describe bioisosterism, the ability of certain chemical groups to function as or mimic other chemical groups.[1][2]
“Atoms anywhere up to four places in the periodic system before an inert gas change their properties by uniting with one to four hydrogen atoms, in such a manner that the resulting combinations behave like pseudoatoms, which are similar to elements in the groups one to four places respectively, to their right.”[3]According to Grimm, each vertical column (of Table below) would represent a group of isosteres.
References
Grimm's hydride displacement law Wikipedia(Text) CC BY-SA