Metal deficiency defect is shown by ${\mathrm{Fe}}_{0.93}\mathrm{O}$. In the crystal, some ${\mathrm{Fe}}^{2+}$ cations are missing and loss of positive charge is compensated by the presence of ${\mathrm{Fe}}^{3+}$ ions. The percentage of ${\mathrm{Fe}}^{2+}$ ions in the ${\mathrm{Fe}}_{0.93}\mathrm{O}$ crystals is (Nearest integer)