Crystal chemical properties and some physical and chemical properties were studied for three polymorphic modifications of rhodium sesquioxide α-Rh2O3, β-Rh2O3, γ-Rh2O3 with corundum-related crystal structures. Our results are compared with literature data. Distinctions, common features, portability, and interrelationship for these crystal structures are discussed. Correlations between crystallographic parameters, electrical conductivity, and thermal stability of these crystalline phases are revealed. Possible reasons for these correlations are discussed.