NITRIDE CHLORIDES OF THE EARLY LANTHANIDES - [M(2)N]CL-3(M=LA-ND)

The nitride chlorides [M(2)N]Cl-3 (M=La-Nd) have been synthesized by r eactions of MCl(3), M and NaN3 in sealed quartz-glass ampoules at 850 degrees C. The structures of [Pr2N]Cl-3 (orthorhombic, Ibam, a=1353.1( 1) pm, b=685.12(9) pm, c=610.72(9) pm) and [Nd2N]Cl-3 (orthorhombic, P bcn, a=1338.2(2) pm, b=684.62(9) pm, c=618.15(9) pm) were determined b y X-ray single-crystal diffraction. [Nd2N]Cl-3 is isotypic with [Gd2N] Cl-3. Although the crystal structures of [M(2)N]Cl-3 (M=La-Nd) contain almost identical anti-SiS2-analogous chains (1)(infinity)[M(4/2)N](3), the symmetry of the nitride chlorides with La, Ce and Pr is somewha t different. The lattice parameters of [La2N]Cl-3 (orthorhombic, Ibam, a=1375.8(3) pm, b=692.2(2) pm, c=618.5(2) pm) and [Ce2N]Cl-3 (orthorh ombic, Ibam, a=1359.0(2) pm, b=686.9(2) pm, c=610.7(1) pm) were calcul ated from powder X-ray Guinier data on the basis of the structural dat a of [Pr2N]Cl-3.