The presence of SmCrO 4 is experimentally established. In Mg 2 + -substituted SmCrO 3 , single-phase perovskite Sm(Cr 1 - x Mg x )O 3 , where x=0-0.23, are formed at ~830 o C by decomposition of Sm(Cr 1 - x Mg x )O 4 which crystallizes at 530-570 o C from amorphous materials prepared by the hydrazine method. Sm(Cr 1 - x Mg x )O 3 solid solution powders consisting of submicrometer-size particles are sinterable; dense materials can be fabricated by sintering for 2h at 1700 o C in air. The relative densities, grain sizes, and electrical conductivities increase with increased Mg 2 + content. Sm(Cr 0 . 7 7 Mg 0 . 2 3 )O 3 materials exhibit an excellent direct current electrical conductivity of 2.2x10 3 Sm - 1 at 1000 o C.