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Syntheses, Structures, and Magnetic Properties of Np3s5 and Np3se5

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Syntheses, Structures, and Magnetic Properties of Np3s5 and Np3se5 1084 Inorg. Chem. 2011, 50, 1084–1088 DOI: 10.1021/ic101915x Syntheses, Structures, and Magnetic Properties of Np3S5 and Np3Se5 Geng Bang Jin,†,‡ S. Skanthakumar,‡ Richard G. Haire,§ L. Soderholm,*,‡ and James A. Ibers*,† †Department of Chemistry, Northwestern University, Evanston, Illinois, 60208-3113, United States, ‡Chemical Science and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, United States, and §Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States Received September 18, 2010 Black prisms of Np3Q5 (Q = S, Se) have been synthesized by the stoichiometric reactions between Np and Q at 1173 K in a CsCl flux. The structures of these compounds were characterized by single-crystal X-ray diffraction methods. The Np3Q5 compounds are isostructural with U3Q5. The structure of Np3Q5 is constructed from layers of Np(1)Q8 distorted bicapped trigonal prisms that share faces with each other on bc planes. Each Np(1)Q8 layer further shares Q(2) edges with two adjacent identical neighbors to form a three-dimensional framework. The space inside each channel within this framework is filled by one single edge-sharing Np(2)Q7 distorted 7-octahedron chain running along the b axis. Magnetic susceptibility measurements show that Np3S5 and Np3Se5 have antiferromagnetic orderings at 35(1) and 36(1) K, respectively. Above the magnetic ordering temperatures, both Np3S5 and Np3Se5 behave as typical Curie-Weiss paramagnets. The effective moments obtained from the fit of the magnetic data to a modified Curie- Weiss law over the temperature range 70 to 300 K are 2.7(2) μB (Np3S5) and 2.9(2) μB (Np3Se5). Introduction chalcogens to form Q-Q bonds. In these NpxQy compounds formal oxidation states of þ3andþ4 are found for Np; in Binary actinide chalcogenides AnxQy (An = actinide; Q = S, Se, Te) exist in a variety of crystal structures and chemical contrast aqueous species exhibit stable oxidation states for - þ þ þ þ 5 compositions with An/Q ratios between 1:1 and 1:5.1 3 As Np of 4, 5, 6, and, under very alkaline conditions, 7. a result, they exhibit a wide range of electronic and magnetic The An3Q5 (An= U, Np; Q = S, Se) compounds are of properties. Among these, 20 Np Q compounds with formulas particular interest because they are borderline between the x y metal-like actinide-rich compounds and the semiconducting of NpQ (Q = S, Se, Te), Np3Q4 (Q = S, Se, Te), Np2Q3 (Q = S, Se, Te), Np Q (Q = S, Se), NpQ (Q = S, Te), chalcogen-rich phases. Both charge balance and crystal 3 5 2 structures suggest that these compounds contain An3þ and Np2Q5 (Q = S, Se), and NpQ3 (Q = S, Se, Te) have been 4þ identified.2,4 Most of these compounds have been character- An in a ratio of 2:1, consistent with the interpretation of ized only by powder X-ray diffraction analyses, and their X-ray photoelectron spectroscopic measurements on com- 237 € physical properties have not been fully studied. It is interest- parable U compounds and with Np Mossbauer spectro- scopic measurements.4,6-12 The chemical formula can thus ing that binary neptunium chalcogenides exhibit a very rich 3þ 4þ 2- be written as (An )2(An )(Q )5.U3S5 and U3Se5 have structural chemistry compared to binary neptunium oxides, 6,7,11,13-16 2 been extensively studied. They crystallize in the which comprise only two stable phases, NpO2 and Np2O5. 3þ 4þ This difference arises in part because of the propensity of space group Pnma with U and U cations occupying the *To whom correspondence should be addressed. E-mail: [email protected] (5) Williams, C. W.; Blaudeau, J. P.; Sullivan, J. C.; Antonio, M. R.; J. Am. Chem. Soc. 123 – (L.S.), [email protected] (J.A.I.). Phone þ1 630 252 4364 Bursten, B.; Soderholm, L. 2001, , 4346 4347. þ þ (6) Potel, M.; Brochu, R.; Padiou, J.; Grandjean, D. C. R. Seances Acad. (L.S.), 1 847 491 5449 (J.A.I.). Fax: 1 847 491 2976 (J.A.I.). Sci., Ser. C 275 – (1) Grenthe, I.; Drozdzynski, J.; Fujino, T.; Buck, E. C.; Albrecht- 1972, , 1419 1421. (7) Moseley, P. T.; Brown, D.; Whittaker, B. Acta Crystallogr. 1972, B28, Schmitt, T. E.; Wolf, S. F. In The Chemistry of the Actinide and Transactinide 1816–1821. Elements, 3rd ed.; Morss, L. R., Edelstein, N. M., Fuger, J., Eds.; Springer: (8) Marcon, J.-P. C. R. Seances Acad. Sci., Ser. C 1967, 265, 235–237. Dordrecht, The Netherlands, 2006; Vol. 1, pp 253-698. (9) Marcon, J.-P. Commis. Energ. At. [Fr], Rapp. 1969, CEA-R-3919, (2) Yoshida, Z.; Johnson, S. G.; Kimura, T.; Krsul, J. R. In The Chemistry 1-99. of the Actinide and Transactinide Elements, 3rd ed.; Morss, L. R., Edelstein, (10) Damien, D.; Damien, N.; Jove, J.; Charvillat, J. P. Inorg. Nucl. Chem. N. M., Fuger, J., Eds.; Springer: Dordrecht, The Netherlands, 2006; Vol. 2, Lett. 1973, 9, 649–655. pp 699-812. (11) Kohlmann, H.; Beck, H. P. J. Solid State Chem. 2000, 150, 336–341. (3) Manos, E.; Kanatzidis, M. G.; Ibers, J. A. In The Chemistry of the (12) Thevenin, T.; Jove, J.; Pages, M.; Damien, D. Solid State Commun. Actinide and Transactinide Elements, 4th ed.; Morss, L. R., Edelstein, N. M., 1981, 40, 1065–1066. Fuger, J., Eds.; Springer: Dordrecht, The Netherlands, 2010; Vol. 6, pp 4005- (13) Suski, W.; Reizer-Netter, H. Bull. Acad. Pol. Sci., Ser. Sci. Chim. 4078. 1974, 22, 701–707. (4) Thevenin, T.; Jove, J.; Pages, M. Hyperfine Interact. 1984, 20,173–186. (14) No€el, H.; Prigent, J. Phys. BþC 1980, 102, 372–379. pubs.acs.org/IC Published on Web 12/28/2010 r 2010 American Chemical Society Article Inorganic Chemistry, Vol. 50, No. 3, 2011 1085 a,b Wyckoff positions 8d (site symmetry 1) and 4c (site symme- Table 1. Crystal Data and Structure Refinements for Np3S5 and Np3Se5 6,7 try .m.), respectively. U3S5 is a semiconductor and ferro- Np3S5 Np3Se5 magnet (Tc = 29 K) that displays a large negative magne- 11,14,16 toresistance effect. U3Se5 is also a semiconductor; it Fw 871.30 1105.80 13,15 a (A˚) 11.7435(6) 12.2863(5) orders ferromagnetically below 24 K. U3Te5 adopts a 17 b (A˚) 8.0479(4) 8.3499(4) different structure type. In contrast, Np3Q5 (Q=S, Se) have c (A˚) 7.4108(4) 7.7583(3) been identified only from powder X-ray diffraction data from V (A˚3) 700.40(6) 795.92(6) F 3 which it was deduced that they are isostructural with c (g/cm ) 8.263 9.228 -1 U S .4,8-10,12 Electrical resistivity measurements on a cold- μ (cm ) 455.51 616.39 3 5 R(F)c 0.0183 0.0222 pressed powder pellet have shown that Np3S5 is a semicon- 2 d 18 Rw(Fo ) 0.0405 0.0474 ductor, whereas Np3Se5 exhibits semimetallic behavior. There are no reliable magnetic data for Np Q , although a For both structures, orthorhombic system, space group=Pnma, Z=4, 3 5 λ ˚ b 237Np Mossbauer€ measurements at 4.2 K have suggested that = 0.71073 A, and T = 100(2) K. From room-temperature X-ray diffraction powder data in refs 9 and 10: a = 11.71(2) A˚, b = 8.07(1) A˚, the magnetic moment of Np should order at low temper- c = 7.42(1) A˚for Np S ; a = 12.24(2) A˚, b = 8.43(1) A˚, c = 7.75(1) A˚ 4,12 3 5 atures. for Np3Se5. No structural parameters were presented; it wasP deduced c || | - | The syntheses of powder samples of Np Q have included thatP these compounds were isostructural withP U3S5. R(F)=P Fo 3 5 2 2 d 2 2 2 2 4 1/2 Fc||/ |Fo| for Fo >2σ(Fo ). Rw(Fo )={ w(Fo - Fc ) / wFo } direct reactions between Np or NpHx and Q, or thermal -1 2 2 2 2 2 -1 2 2 2 4,8,10,12 for all data. w =σ (Fo ) þ (qFo ) for Fo g 0; w =σ (Fo )forFo <0. decomposition of NpQ3. Here we report the syn- q = 0.0152 for Np3S5, 0.0101 for Np3Se5. theses of large single crystals of Np3S5 and Np3Se5 by a different route. These crystals have enabled us to examine intensity data as well as cell refinement and data reduction were 21 more thoroughly their structures and magnetic properties. carried out with the use of the program APEX2. Absorption corrections for Np3Se5 (face indexed) and Np3S5, as well as Experimental Section incident beam and decay corrections were performed with the use of the program SADABS.22 The structures were solved with Syntheses. S (Alfa-Aesar, 99.99%), Se (Cerac 99.999%), and the direct-methods program SHELXS and refined with the least- CsCl (Strem Chemicals, 99.999%) were used as received. Brittle squares program SHELXL.23 The program STRUCTURE pieces of high-purity arc-melted 237Np metal (ORNL) were TIDY24 was used to standardize the positional parameters. crushed and used in these syntheses. Additional experimental details are given in Table 1 and in the Caution! 237Np and any ingrown daughter products are R- and Supporting Material. β-emitting radioisotopes and as such are considered a health risk. Powder X-ray Diffraction Measurements. Powder X-ray dif- Its use requires appropriate infrastructure and personnel trained in fraction patterns were collected with a Scintag XGEN-4000 the handling of radioactive materials. The procedures we use for diffractometer with the use of Cu KR radiation (λ = 1.5418 A˚).
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