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NEET2006ChemistrySolid StateActual

The appearance of colour in solid alkali metal halides is generally due to:

Options

  1. Ainterstitial positions
  2. BF-centres
  3. CSchottky defect
  4. DFrenkel defect

Correct answer

B. F-centres

Step-by-step solution

The appearance of colour in solid alkali metal halides is generally due to F-centres. Related Theory The anion sites occupied by electrons are called F-centre. An F-centre is a type of crystallographic defect in which an anionic vacancy in a crystal lattice is occupied by one or more unpaired electrons.

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