Question

Barium titanate has the perovskite structure, i.e., a cubic lattice with $B{a}^{2+}$ ions at the corners of the unit cell, oxide ions at the face centres and titanium ions at the body centre. The molecular formula of barium titanate is:

• A. $BaTi{O}_3$
• B. $BaTi{O}_4$
• C. $BaTi{O}_2$
• D. $BaTiO$

Answer 1

Answer: (A)

$BaTi{O}_3$

Barium titanate has the perovskite structure, i.e., a cubic lattice.
$B{a}^{2+}$ions at the corners of the unit cell.
There are 8 face centre positions each contributing one eight to the unit cell.
There is $\frac{8}{8}=1$ Ba(II) ion per unit cell.
Oxide ions at the face centres. There are six face centre positions each contributing one half to the unit cell.
There are $\frac{6}{2}=3$ oxide ions per unit cell.
Titanium ions at the body centre.
There is one body centre position contributing one to the unit cell.
There is one $Ti$ ion per unit cell.
The molecular formula of barium titanate is $BaTi{O}_3$