Neptunium Thiophosphate Chemistry: Intermediate Behavior between Uranium and Plutonium

Journal Article · Sat Jan 01 04:00:00 EST 2011 · Inorganic Chemistry

DOI:https://doi.org/10.1021/ic201493w· OSTI ID:1055145

Jin, Geng Bang ^[1]; Skanthakumar, S ^[2]; Haire, Richard G. ^[3]; Soderholm, L ^[2]; Ibers, James A. ^[1]

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1. Northwestern University, Evanston
2. Argonne National Laboratory (ANL)
3. Oak Ridge National Laboratory (ORNL)

Black crystals of Np(PS4), Np(P2S6)2, K11Np7(PS4)13, and Rb11Np7(PS4)13 have been synthesized by the reactions of Np, P2S5, and S at 1173 and 973 K; Np, K2S, P, and S at 773 K; and Np, Rb2S3, P, and S at 823 K, respectively. The structures of these compounds have been characterized by single-crystal X-ray diffraction methods. Np(PS4) adopts a three-dimensional structure with Np atoms coordinated to eight S atoms from four bidentate PS4 3 ligands in a distorted square antiprismatic arrangement. Np(PS4) is isostructural to Ln(PS4) (Ln = LaNd, Sm, GdEr). The structure of Np(P2S6)2 is constructed from three interpenetrating diamondtype frameworks with Np atoms coordinated to eight S atoms from four bidentate P2S6 2 ligands in a distorted square antiprismatic geometry. The centrosymmetric P2S6 2 anion comprises two PS2 groups connected by two bridging S centers. Np(P2S6)2 is isostructural to U(P2S6)2. A11Np7(PS4)13 (A = K, Rb) adopts a threedimensional channel structure built from interlocking [Np7(PS4)13]11-screw helices with A cations residing in the channels. The structure of A11Np7(PS4)13 includes four crystallographically independent Np atoms. Three are connected to eight S atoms in bicapped trigonal prisms. The other Np atom is connected to nine S atoms in a tricapped trigonal prism. A11Np7(PS4)13 is isostructural to A11U7(PS4)13. From NpS bond distances and charge-balance, we infer that Np is trivalent in Np(PS4) and tetravalent in Np(P2S6)2 and A11Np7(PS4)13.Np exhibits a behavior intermediate betweenUand Pu in its thiophosphate chemistry.

• Research Organization: Oak Ridge National Laboratory (ORNL)
• Sponsoring Organization: SC USDOE - Office of Science (SC)
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 1055145
• Journal Information: Inorganic Chemistry, Journal Name: Inorganic Chemistry Journal Issue: 19 Vol. 50; ISSN 0020-1669
• Country of Publication: United States
• Language: English