PREPARATION AND MAGNETIC PROPERTIES OF PEROVSKITE-TYPE COMPOUNDS Sr₃Cr₂WO₉, Ca₃Cr₂WO₉ AND Sr₃Cr₂UO₉.

Single phases of Sr//3Cr//2WO//9 with different ferrimagnetic Curie temperatures, Tc equals 448K, 473K and 509K, were prepared in the three different conditions, 1400 degree C in P(O//2) equals 2. 4 multiplied by 10** minus **1**3 atmosphere, 1300 degree C in P(O//2) equals 3 multiplied by 10** minus **1**6 atmosphere and 1200 degree C in P(O//2) equals 10** minus **1**5 atmosphere, respectively. Similar compounds Ca//3Cr//2WO//9 and Sr//3Cr//2UO//9 were prepared at 1300 degree C in Ar and at 1400 degree C in Ar plus H//2O atmosphere, respectively. Cation orderings of Cr**3** plus and W**6** plus or U**6** plus were complete in both compounds.