In the Wikipedia article on crystallographic defects, a type of point defect known as an interstitial defect is described as follows:

Interstitial defects are atoms that occupy a site in the crystal structure at which there is usually not an atom. They are generally high energy configurations. Small atoms (mostly impurities) in some crystals can occupy interstices without high energy, such as hydrogen in palladium.

What is meant here by "high energy configurations"? If these defects possess a "high energy configuration", then it sounds like they would be difficult to come about? If so, then how do these defects come about (where do they gain the energy from to occur)?

I would greatly appreciate it if people would please take the time to clarify this.


Yes, interstitial defects increase potential energy, as stated in Wikipedia: "In interstitial defects three or more atoms may share one lattice site, thereby increasing its total energy." See Physics on StackExchange for an explanation of potential energy in crystals.

How can they form? One example is during rapid crystallization, where there is insufficient time for atoms to segregate. Think of this as "freezing in place" a defect. If warmed and cooled again, the defect can be excluded and a more-perfect crystal forms. This is the basis for the zone refining, Czochralski process and float-zone purification, where extremely slow crystal growth allows time for impurities to be pushed out.

On the other hand, one can intentionally induce interstitial defects through repeated folding, heating, and cooling to make metals harder and tougher, such as Wootz or Damascus steel. It is easy to see how this laborious process requires energy to insert the defects.

  • $\begingroup$ Thanks for the answer. So "high energy configuration" is referring to a configuration that has high potential energy? If so, then what does it mean for a configuration to have "high potential energy"? What are the consequences of this? $\endgroup$ – The Pointer Jan 19 '20 at 3:03
  • 1
    $\begingroup$ That question has already been answered in Physics, physics.stackexchange.com/questions/328365/… $\endgroup$ – DrMoishe Pippik Jan 19 '20 at 3:40
  • $\begingroup$ I understand now; thanks! But it wont allow me to award you the bounty? $\endgroup$ – The Pointer Jan 19 '20 at 4:11
  • $\begingroup$ Never mind; I am now able to award the bounty. $\endgroup$ – The Pointer Jan 19 '20 at 15:14

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.