Definition
Plain language
A gap between atoms in a solid where a small extra atom can sit.
As stated in the literature
Void position in a crystal lattice (e.g. octahedral or tetrahedral) that can host small solute atoms such as hydrogen in palladium.
Also called: interstitial sites
Why it matters: These gaps explain how some metals can absorb far more of a gas than seems physically possible, which underpins both real hydrogen storage and some overreaching claims.
For example, hydrogen atoms are small enough to tuck into the gaps between palladium atoms without disturbing the metal's overall structure.
Heard on the show
“" It asks about the difference in behavior between isotopic hydrogen at two kinds of interstitial sites.”Episode 240 — Frontier Models Designed Follow-Ups To Fraudulent Papers 93% Of The Time