Quaternary Thorium Transition Metal Pnictide Oxides: ThCu^j-PO, ThCuAsO, and Th2Ni3 _xP3
نویسندگان
چکیده
The new compounds T hC u^PO and ThCuAsO with ZrCuSiAs-type structure were pre pared in well crystallized form by chemical vapor transport reactions. Th2Ni3.A:P30 with a new structure type was obtained by reaction of T h 0 2 with the other elemental components in an alumina crucible at high temperatures. The crystal structures of the three compounds were determined from single-crystal X-ray data. ThCuj.xPO: P4/nmm, a = 389.43(4), c 828.3(1) pm, R = 0.024 for 13 variable parameters and 338 structure factors; ThCuAsO: P4/ nmm, a = 396.14(5), c = 844.0(1) pm, R = 0.028 (13 variables and 379 F values); Th2Ni3_JP30 : P4/nmm, a = 394.62(4), c = 1723.2(3) pm, R = 0.018 (27 variables and 374 F values). The refinement of the occupancy parameters revealed significant deviations from the ideal values for the transition metal sites for two compounds resulting in the exact compositions ThCu0938(4)PO and Th2Ni2 45(nP30 . Magnetic susceptibility measurements indicate Pauli paramagnetism for ThCu^PO. The crystal structures of these compounds are closely related. They belong to a large family of tetragonal structures of which the ThCr2Si2and the PbFCltype structures are well known examples.
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