NEW OXYCHLORIDES OF THE RARE-EARTH-METALS WITH VANADIUM AND RHENIUM

i) New compounds Ln(12.33)V(6)O(23)(OH)Cl-20 (Ln = La, Ce) were prepar ed by heating mixtures of LnCl(3), LnOCl and V2O5 (4:8:3) in evacuated , sealed silica ampoules (850 degrees C, 4 d). Single crystals could b e obtained by chemical vapor transport (T-2-->T-1, T-2 = 900 degrees C , T-1 = 800 degrees C, 14d, p(Cl-2, 298K) approximate to 70 mbar). The single-crystal study of the lanthanum compound [a = 17.8818(25)Angstr om, c = 4.0567(7) Angstrom, Z = 1, 1035 independent I-0, 70 parameters , R1 = 3.52%] showed that vanadium has CN=4 (tetrahedrally) and lantha num has CN = 9 (threefold capped trigonal prismatic). A strong relatio nship to the structures of the Pr3NbO4Cl6-and the La2TaO4Cl3-type coul d be discussed. ii) Further we obtained dark red powder of La3ReO6Cl3 by heating (740 degrees C, 5 d) a mixture of ReO3 and LaOCl (1:3) in s ealed silica ampoules under argon atmosphere (p(Ar, 298K)= 1 atm). Thi s new rhenium-compound crystallizes in the hexagonal space group P6(3) /m (No.176) [a = 9.4164(6) Angstrom, c = 5.4248(4) Angstrom] and is is ostructural to La3WO6Cl3.