Classification of hydrides (ionic, covalent, metallic, interstitial) (Ionic hydrides (salt-like, H⁻ with very electropositive metals); covalent (molecular)
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Ionic hydrides (salt-like, H⁻ with very electropositive metals); covalent (molecular, mainly p-block); metallic; interstitial (H in voids of transition metals).
What each symbol means
| Symbol | What it stands for |
|---|---|
| Ionic | Alkali and alkaline earth hydrides (e.g. NaH, CaH₂); H as hydride ion |
| Covalent | p-block hydrides (CH₄, NH₃, H₂O) and similar covalent E–H bonds |
| Metallic | d/f-block metals absorbing H with metallic conductivity |
| Interstitial | Non-stoichiometric hydrogen in crystal voids (e.g. TiHₓ, PdHₓ) |
When to use this
Classification is textbook-level for JEE; borderline cases (BeH₂, MgH₂) are often taught as covalent/polymeric rather than purely ionic.