Interstitial defect
= Interstitial defect
An interstitial defect is an atom occupying a position between the regular atomic positions in a <crystal structure>. Small solute atoms or an extra host atom can occupy such positions. Different interstitial orientations can induce anisotropic local strain; an applied <stress> changes their relative energies. Thermally activated hopping among those positions can then produce delayed elastic strain and the <Snoek effect>.