Properties Of Interstitial Compounds

What are Interstitial Compounds?

The compounds formed when small atoms of H, C or N get trapped inside the crystal lattice of metals are known as interstitial compounds. A number of interstitial compounds are formed by the transition metals. Transition metals react with elements such as hydrogen, carbon, nitrogen, boron etc. to form interstitial compounds.

  • As vacant spaces of the transition metals are filled up by small atoms, these compounds are hard and rigid.
  • The chemical properties of the parent transition metals are not altered during the formation of interstitial compounds.
  • However, there are various changes in the physical properties such as density, rigidity, hardness, malleability, ductility, electrical conductivity etc.
  • Steel and cast iron are the interstitial compounds of iron which are formed with carbon. In the formation of these compounds, the malleability and ductility of iron are lost to a great extent, but the tenacity of the metal increases.

Transition metals have crystals which are either hexagonal close-packed or face-centered cubic structures. Both of these lattices are very similar and have two type of holes.

  • Firstly, there can be two tetrahedral holes per metal atom that mean there is a hole between four metal atoms.
  • Secondly, there can be one octahedral hole per atom that is the hole is between six metal atoms.

Physical and chemical properties

Following are the significant physical and chemical properties of the interstitial compounds:

  1. These compounds have very high melting points, higher than that of the parent transition metals.
  2. These compounds are very hard. The hardness of some borides is comparable to that of a diamond.
  3. The conductivity exhibited by them is similar to their parent metal.
  4. These compounds are chemically inert in nature.

We have gone through the interstitial compounds and their physical and chemical properties. For any further query on this topic please install Byju’s the learning app.


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Which of the following statements is/are true