In Mg2+-substituted LaCrO3, single-phase perovskite compounds La(Cr1-xMgx)O-3, where x = 0 to 0.28, have been formed at low temperatures (similar to 800 degrees C) by decomposition of La(Cr1-xMgx)O-4 which crystallizes at similar to 550 degrees C from amorphous materials prepared by the hydrazine method. La(Cr1-xMgx)O-3 powders consisting of submicrometer-size are highly sinterable; dense materials can be fabricated by sintering for 2 h at 1600 degrees C under atmospheric pressure. The relative densities, grain sizes, electrical conductivities, and thermal expansion coefficients of the materials increase with increased Mg2+ content. La(Cr0.75Mg0.25)O-3 materials show an excellent electrical conductivity at elevated temperatures. Their thermal expansion coefficient is in good agreement with that of cubic ZrO2(10Y) as an electrolyte.