In NiO, the Ni-O internuclear separation is 209 pm. Determine the volume of a unit cell of NiO and its density (assume a non-defect structure). Given…

In NiO, the Ni-O internuclear separation is 209 pm. Determine the volume of a unit cell of NiO and its density (assume a non-defect structure). Given that the observed density of NiO is 6.67 g cm-3, determine the extent of vacancies in the NiO lattice. Express your answer as a percentage.