What are the formulae of the compounds formed when lanthanoids (Ln) react with nitrogen and halogen…

What are the formulae of the compounds formed when lanthanoids (Ln) react with nitrogen and halogen respectively?
  1. $\mathrm{LnN}$ and $\mathrm{LnX}_3$
  2. $\mathrm{LnN}_3$ and $\mathrm{LnX}$
  3. $(\mathrm{Ln})_2 \mathrm{~N}_3$ and $\mathrm{LnX}_3$
  4. $\operatorname{LnN}$ and $\operatorname{LnX}$

Solution

Lanthanoids possess common oxidation state +3 $\mathrm{Ln}^{+3}+\mathrm{N}^{-3} \rightarrow \mathrm{LnN}$ (with Nitrogen) $\mathrm{Ln}^{+3}+\mathrm{X}^{-1} \rightarrow \mathrm{LnX}_3$ (with halogen)

Asked in: MHT CET 2021 (20 Sep Shift 1)

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