F-Centres are:

Consider the following statements I. NaCl and KCl show metal excess defect due to anionic vacancies II. F- centres are the anionic site occupied by unpaired electrons III. F-centres is derived from the germen word farbenzenter for colour centre . F-centres impart yellow colour to the NaCl crystals Which of the above statements is / are correct ?

F-centre is

F-centre is

The presence of F-centres in a crystal makes it

The presence of F-centres in a crystal makes it

The presence of F-centres in a crystal makes it

What is F-centres ?