Frenkel and Schottky defects are
nucleus defects
non-crystal defects
crystal defects
nuclear defects
In the crystal of CsCl, the co-ordination number changes from 8:8 to 6:6 by:
applying high pressure
applying low temperature
applying high temperature
applying low pressure
A compound CuCl has face-centred cubic structure. Its density is 3.4 g cm-3 , The length of unit cell is:
8.734
5.834
5.783
8.153
If the positions of Na+ and Cl- are interchanged in NaCl , the crystal lattice with respect to Na+ and CI- is:
bcc and fcc
fcc and bcc
both fcc
both bcc
ZnO is white when cold and yellow when heated. It is due to the development of
Frenkel defect
metal excess defect
Schottky defect
metal deficiency defect.
B.
metal excess defect
ZnO turns yellow on heating as Zn2+ ions move in interstitial sites and electrons also get entrapped in nearby interstitial sites to maintain electrical neutrality. As extra Zn2+ ions are present in interstitial sites thus, it is metal excess defect.
Among the following, the compound that is both paramagnetic and coloured is
K2Cr2O7
(NH4)2[TiCl6]
VOSO4
K3[Cu(CN)4]
If an atom crystallises in bee lattice with r= 4 Å then the edge length will be
2 Å
8 Å
2.39 Å
9.23 Å
A mineral having the formula AB2 crystallizes in the cubic close-packed lattice , with the A atoms occupying the lattice points. The fraction of the tetrahedral sites occupied by B atoms is :
20 %
40 %
60 %
100 %
A forms hcp lattice and B are occupying 1/3rd of tetrahedral voids, then the formula of compound is
AB
A3B2
A2B3
AB4