The temperature dependencies of the unit cell volumes of rock-salt CoO-ZnO solid solutions are shown in Fig. and Table . Note that for the ZnO-rich compositions (Co 0.3 Zn 0.7 O and Co 0.4 Zn 0.6 O) the V(T) dependence is essentially quadratic, whereas for the other compositions this dependence is either linear or quasilinear (Table ).