🎴 Flashcard Mode
Solid State Chemistry - Point Defects and Interstitial Compounds
Card1 / 13
Mastered0
Review0
QuestionClick to flip
The anionic sites occupied by unpaired electrons are called F-centers or colour centers. They impart ______ $(X)$ colour to the crystals on $NaCl.$ Excess of lithium makes $LiCl$ crystals ______ $(Y)$ and excess of potassium makes $KCl$ crystals ______ $(Z)$. $(X)$, $(Y)$ and $(Z)$ are:
AnswerClick to flip back
A
yellow, pink and violet (or lilac) respectively.
💡 Explanation:
$NaCl$ shows the metal excess defect, which results in the formation of an F-center in the crystal. When light falls on this crystal, the electron in F-center gets excited. This F-center is then responsible for the yellow $(X)$ color of $NaCl$.
In a similar way, the excess of lithium imparts Pink $(Y)$ colour of $LiCl$ crystals.
In a similar way, the excess of potassium imparts violet/lilac $(Z)$ colour of $KCl$ crystals.