A ternary compound, Eu2MnZrO7-delta was synthesized in a reducing atmosphere at 1623 K. The compound has the basic cell of the fluorite type. Electron diffraction patterns consisted of the diffuse reflections in addition to the fundamental reflections. In the dark-field image, the existence of microdomains with different orientations was observed. Each domain has a modulation along the [111](*) of the basic cell with a sequence of the 1/2(111)(*). It is suggested that the divalent mangnese ions, Mn2+, were formed in the reducing atmosphere, which resulted in the formation of the fluorite-type compound.