Which defect leads to decrease in the density of crystal?

In a normal spinel type structure, the oxide ions are arranged in ccp, whereas $$1 / 8$$ tetrahedral holes are occupied by $$\mathrm{Zn}^{2+}$$ ions and $$50 \%$$ of octahedral holes are occupied by $$\mathrm{Fe}^{3+}$$ ions. The formula of compound is

$$\mathrm{NaCl}$$ has face centred structure with edge length equal to $$361 \mathrm{~pm}$$. The radius is

Doping of silicon (Si) with indium (In) leads to the formation of

Which of the following show both Frenkel and Schottky defect?

How many atoms are present in hcp per unit cell?

Sodium metal crystallises in a body centred cubic lattice with a unit cell edge of 4.29 $$\mathop A\limits^o $$. The radius of sodium atom is

How much part of any corner atom actually belongs to a particular unit cell?

The vacant space in bcc lattice cell is

Graphite is a soft solid lubricant extremely difficult to melt. The reason for this anomalous behaviour is that, graphite