# Titanium monoxide has a rock−salt structure. X−ray diffraction data show that the length of one edge of the cubic unit cell for TiO with a 1:1 ratio of Ti to O is 4.18$A^{\large\circ}$, and the density as determined by volume and mass measurements is 4.92 g $cm^{–3}$. Do the data indicate that defects are present? If so, are they vacancy or interstitial defects? [Ti = 47.88 u].

density is d=$\large\frac{4(47.88+16)}{6.023\times 10^{23}(4.18\times 10^{23})}=$$4.81gcm^{-3}$