Which of the following transition metal oxides represents a "mixed oxide" structurally incorporating — d and f Block Elements Chemistry Question

💡 Solution & Explanation

A mixed oxide consists of a single metal existing in two distinct oxidation states. $Mn_3O_4$ is actually a physical combination of $MnO$ (where $Mn$ is $+2$) and $Mn_2O_3$ (where $Mn$ is $+3$). Similarly, $Fe_3O_4$ and $Co_3O_4$ are classic examples of mixed oxides in the $3d$ transition series. The others listed exist in a single stable oxidation state ($Cr^{3+}$, $V^{5+}$, $Ti^{4+}$).