Preparation, crystal structure, and physical properties of the uranium nickel phosphide U{sub 3}Ni{sub 3.34}P{sub 6}
- Universitaet Muenster (Germany)
The new ternary phosphide U{sub 3}Ni{sub 3.34}P{sub 6} was prepared by reaction of the elemental components in a tin flux and its crystal structure was determined from single-crystal X-ray data: P4/mmm, a = 381.8(1) pm, c = 1350.1(4) pm, Z = 1, and R = 0.018 for 200 structure factors and 18 variable parameters. The ideal composition is U{sub 3}Ni{sub 4}P{sub 6}; however, the nickel site was found to be occupied to only 83.6(5)%. The formation of these defects is rationalized from bonding considerations. One phosphorus site had to be refined with a split position and models suggesting various kinds of short-range order for this position are discussed. U{sub 3}Ni{sub 3.34}P{sub 6} contains two different uranium sites, which are assigned the oxidation numbers +3 and +4 on the basis of their differing U-P bond lengths. The structure is related to the structures of several tetragonal transition metal phosphides and arsenides, e.g., UNi{sub 1.51}P{sub 2} with ThCr{sub 2}Si{sub 2} type structure and U{sub 2}Cu{sub 4}As{sub 5}. Magnetic susceptibility measurements suggest ferrimagnetism with the Curie temperature T{sub C} = 139(2) K, the Weiss constant {Theta} = 107(3) K, and a magnetic moment of {mu}{sub exp} = 2.1(1) {mu}{sub B} per average uranium atom. Four-probe electrical conductivity measurements indicate semimetallic behavior.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 146474
- Journal Information:
- Journal of Solid State Chemistry, Vol. 116, Issue 2; Other Information: PBD: May 1995
- Country of Publication:
- United States
- Language:
- English
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