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A new binary compound, NpSe2, possesses metal-chalcogen and chalcogen-chalcogen interactions different from those reported for other metal dichalcogenides. Its structure is incommensurately modulated and features linear Se chains and valence-ambiguous Np cations.

A neutral-framework thorium oxohydroxosulfate hydrate has been isolated from aqueous solution. This microporous structure, which self-assembles without a templating agent, is built from [Th6(OH)4O4(H2O)6]12+ hexamers and thorium(IV) monomers linked through bridging sulfates. Solution conditions were chosen to enable an active competition between sulfate and hydroxide for thorium coordination. Synthetic requirements are discussed for this rare example of a thorium(IV) polynuclear complex containing mixed oxo-, hydroxo-, and sulfato-bridging moieties.

Colorless crystals of ThSiO4 (I) and (Ca0.5Na0.5) 2NaThSi8O20 (II) are prepared by solid state reactions of ThO2, CaSiO3, and Na2WO4 (evacuated silica ampoules, 1073 K, 140 h).

NaxNpIV(NpVO2)6 (OH)1+xCl9(H2O)8-x (0 < x ≤ 1) is synthesized by evaporation of a neptunium(V) acidic (HCl) stock solution over several months to complete dryness.

Black crystals of (III), (IV), (VI), and (VIII) are synthesized by solid state reactions and their structures are determined by single crystal XRD.

Green crystals of (NpO2)2(SeO4)(H2O)4 (I), (NpO2)2(SeO4)(H2O)2 (II), and (NpO2)2(SeO4)(H2O) (III) are hydrothermally synthesized from mixtures of Na2SeO4 in 2 M aq.

Colorless crystals of CsTh(MoO4)2Cl (I) and Na4Th(WO4)4 (II) are synthesized by solid state reactions of either ThO2, MoO3, and excess CsCl, or ThCl4 and Na2WO4 (silica ampules, 993 K, 120 h).

The black title compounds are synthesized by reactions of the elements in Sb2Q3 (Q: S, Se) fluxes at 900 °C for 7 d and characterized by single crystal XRD, UV/VIS/NIR diffuse reflectance spectroscopy, and magnetic susceptibility measurements.

Black prisms of the title compounds are prepared by reactions of stoichiometric mixtures of Np and S or Se in a CsCl flux at 1173 K for 4 d.

Black prisms of the title compounds are prepared by reactions of the elements using CsCl as a flux (1173 K, 4 d).

The five quaternary neptunium compounds KCuNpS3, RbCuNpS3, CsCuNpS3, KAgNpS3, and CsAgNpS3 (AMNpS3) have been synthesized by the reaction of Np, Cu or Ag, S, and K2S or Rb2S3 or Cs2S3 at 793 K (Rb) or 873 K. These isostructural compounds crystallize as black rectangular plates in the KCuZrS3 structure type in space group Cmcm of the orthorhombic system. The structure comprises MS4 (M = Cu or Ag) tetrahedra and NpS6 octahedra that edge share to form ∞2[MNpS3−] layers. These layers are separated by the alkali-metal cations. The Np−S bond lengths vary from 2.681(2) to 2.754(1) A. When compared to the corresponding isostructural Th and U compounds these bond distances obey the expected actinide contraction. As the structure contains no S−S bonds, formal oxidation states of +1/+1/+4/−2 may be assigned to A/M/Np/S, respectively. From these results a value of 2.57 for the bond-valence parameter r0 for Np4+−S2− has been derived and applied to the estimation of the formal oxidation states of Np in the binary NpxSy...

Dark-red square plates of the previously reported compounds “(UO)2LnS3” (Ln = Yb, Y) have been synthesized by solid-state reactions of UOS and YbS or Y2S3 with Sb2S3 as a flux at 1273 K. The struct...

Red needles of UY{sub 4}O{sub 3}S{sub 5} have been synthesized by the solid-state reaction at 1273 K of UOS and Y{sub 2}S{sub 3} with Sb{sub 2}S{sub 3} as a flux. UY{sub 4}O{sub 3}S{sub 5} adopts a three-dimensional structure that contains five crystallographically unique heavy-atom positions. U and Y atoms disorder on one eight-coordinate metal position bonded to four O atoms and four S atoms and two seven-coordinate metal positions bonded to three O atoms and four S atoms. Another eight-coordinate metal position with two O and six S atoms and one six-coordinate metal position with six S atoms are exclusively occupied by Y atoms. UY{sub 4}O{sub 3}S{sub 5} is a modified Curie-Weiss paramagnet between 1.8 and 300 K. Its effective magnetic moment is estimated to be 3.3(2) mu{sub B}. UY{sub 4}O{sub 3}S{sub 5} has a band gap of 1.95 eV. The electrical resistivity along the [010] direction of a single crystal shows Arrhenius-type thermal activation with an activation energy of 0.2 eV. - Graphical abstract: View of the crystal structure of UY4O3S5.

Three gadolinium scandium chalcogenides have been synthesized using Sb2Q3 (Q=S, Se) fluxes at 975 °C. Gd3.04Sc0.96S6, GdScS3, and Gd1.05Sc0.95Se3 are crystallized in U3ScS6 type, GdFeO3 type, and UFeS3 type structures, respectively. The magnetic susceptibilities for these compounds follow the Curie–Weiss law above their transition temperatures. The effective magnetic moments are close to calculated values for free Gd3+ ions. The Weiss constants for Gd3.04Sc0.96S6, GdScS3, and Gd1.05Sc0.95Se3 are determined to be −3.3(1), −4.5(4), and 1.5(1) K, respectively. Gd3.04Sc0.96S6 orders antiferromagnetically below 9 K. GdScS3 exhibits an antiferromagnetic ordering below 3 K with a weak ferromagnetism. Gd1.05Sc0.95Se3 undergoes a ferromagnetic transition around 5 K. The optical band gaps for Gd3.04Sc0.96S6, GdScS3, and Gd1.05Sc0.95Se3 are 1.5, 2.1, and 1.2 eV, respectively.

Dark red single crystals of PrLnYb{sub 2}S{sub 6} (Ln=Pr/Yb, Tb, Dy) have been synthesized through the reactions of elemental rare earth metals and S using a Sb{sub 2}S{sub 3} flux at 1000 deg. C. These isotypic compounds adopt the F-Ln{sub 2}S{sub 3} three-dimensional open-channel structure type. Eight-coordinate Pr{sup 3+} ions sit in the channels that are constructed from three different edge-shared double chains running down the b-axis that contain Yb(1)S{sub 6} octahedra, Yb(2)S{sub 6} octahedra, and LnS{sub 7} monocapped trigonal prisms. Each double chain connects to four other neighbors by sharing vertices and edges. Considerable disordering in Ln positions was observed in single X-ray diffraction experiments only in the case of Pr/Yb. Least-squares refinements gave rise to the formulas of Pr{sub 1.34}Yb{sub 2.66}S{sub 6}, of PrTbYb{sub 2}S{sub 6}, and PrDyYb{sub 2}S{sub 6}, which are confirmed by the elemental analysis and magnetic susceptibility measurements. Pr{sub 1.34}Yb{sub 2.66}S{sub 6}, PrTbYb{sub 2}S{sub 6}, and PrDyYb{sub 2}S{sub 6} are paramagnetic down to 2 K, without any indications of long-range magnetic ordering. The optical transitions for Pr{sub 1.34}Yb{sub 2.66}S{sub 6}, PrTbYb{sub 2}S{sub 6}, and PrDyYb{sub 2}S{sub 6} are at approximately 1.6 eV. Crystallographic data are listed as an example for PrTbYb{sub 2}S{sub 6}: monoclinic, spacemore » group P2{sub 1}/m, a=10.9496(10) A, b=3.9429(4) A, c=11.2206(10) A, {beta}=108.525(2){sup o}, V=459.33(7) A{sup 3}, Z=2. - Graphical abstract: An illustration of the three-dimensional structure of PrTbYb{sub 2}S{sub 6} viewed along the b-axis.« less

EuLn2Q4 (Ln=Tb–Lu; Q=S, Se) has been synthesized using Sb2Q3 (Q=S, Se) fluxes at 1000 °C. These compounds crystallize in a CaFe2O4-type three-dimensional channel structure that is built from edge-shared double rutile chains of [LnQ6] octahedra running down the b-axis. Each double chain is connected at the vertices to four other double chains to form open channels where bicapped trigonal prismatic Eu2+ ions reside. All of these compounds show antiferromagnetic ordering with Neel temperatures, TN∼3–4 K. The optical band gaps for EuTb2Se4, EuDy2Se4, EuHo2Se4, EuEr2Se4, EuTm2Se4, EuYb2Se4 EuLu2Se4, and EuYb2S4 are found to be 2.0, 1.8, 1.8, 1.7, 1.8, 1.3, 1.7, and 1.6 eV, respectively.

δ-Ln2−xLuxS3 (Ln=Ce, Pr, Nd; x=0.67–0.71) compounds have been synthesized through the reaction of elemental rare-earth metals and S using a Sb2S3 flux at 1000 °C. These compounds are isotypic with CeTmS3, which has a complex three-dimensional structure. It includes four larger Ln3+ sites in eight- and nine-coordinate environments, two disordered seven-coordinate Ln3+/Lu3+ positions, and two six-coordinate Lu3+ ions. The structure is constructed from one-dimensional chains of LnSn (n=6–9) polyhedra that extend along the b-axis. These polyhedra share faces or edges with two neighbors within the chains, while in the [ac] plane they share edges and corners with other chains. Least square refinements gave rise to the formulas of δ-Ce1.30Lu0.70S3, δ-Pr1.29Lu0.71S3 and δ-Nd1.33Lu0.67S3, which are consistent with the EDX analysis and magnetic susceptibility data. δ-Ln2−xLuxS3 (Ln=Ce, Pr, Nd; x=0.67–0.71) show no evidence of magnetic ordering down to 5 K. Optical properties measurements show that the band gaps for δ-Ce1.30Lu0.70S3, δ-Pr1.29Lu0.71S3, and δ-Nd1.33Lu0.67S3 are 1.25, 1.38, and 1.50 eV, respectively. Crystallographic data: δ-Ce1.30Lu0.70S3, monoclinic, space group P21/m, a=11.0186(7), b=3.9796(3), c=21.6562(15) A, β=101.6860(10), V=929.93(11), Z=8; δ-Pr1.29Lu0.71S3, monoclinic, space group P21/m, a=10.9623(10), b=3.9497(4), c=21.5165(19) A, β=101.579(2), V=912.66(15), Z=8; δ-Nd1.33Lu0.67S3, monoclinic, space group P21/m, a=10.9553(7), b=3.9419(3), c=21.4920(15) A, β=101.5080(10), V=909.47(11), Z=8.

Syntheses, Structure, Magnetism, and Optical Properties of Lutetium- based Interlanthanide Selenides Geng Bang Jin, † Eun Sang Choi, ‡ Robert P. Guertin, § James S. Brooks, ‡ Corwin H. Booth, £ and Thomas E. Albrecht-Schmitt †,* Department of Chemistry and Biochemistry and the E. C. Leach Nuclear Science Center, Auburn University, Auburn, Alabama 36849 Department of Physics and National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310 Department of Physics and Astronomy, Tufts University, Medford, Massachusetts 02155 Chemical Sciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Rd., Berkeley, CA 94720 Published in Inorg. Chem. 46, 9213 (2007). Abstract

EuPnSe3 (Pn=Sb, Bi) have been synthesized through the reaction of Eu with Pn2Se3 (Pn=Sb, Bi) and Se at 850–900 °C. These compounds are isotypic with SrPnSe3 (Pn=Sb, Bi) and consist of square pyramidal PnSe5 units and distorted PnSe6 octahedra that form hollow columns that extend along the c-axis. These columns are separated by Eu2+ cations that occur as nine-coordinate tricapped trigonal prisms. There are also additional V-shaped triselenide Se32− anions between the columns that bind the Eu2+ cations. The Se⋯Se contacts (in EuSbSe3) in these units are 2.4584(11) and 2.4359(11) A, which are consistent with Se–Se single bonds. The overall structure is chiral. Bond-valence sum calculations indicate that these compounds contain Eu2+. Magnetic susceptibility measurements provide values of 7.66 μB/Eu for EuSbSe3 and 7.64 μB/Eu for EuBiSe3, which are close to the expected free-ion moment for Eu2+. These compounds follow essentially Curie behavior from 300 to 5 K, and undergo an apparently antiferromagnetic transition below 5 K. Crystallographic data: EuSbSe3, orthorhombic, space group P212121, a = 32.936 ( 2 ) A , b = 15.406 ( 1 ) A , c = 4.2622 ( 3 ) A , V = 2162.7 ( 2 ) A 3 , Z = 16 , R ( F ) = 2.63 % for 183 parameters and 5095 reflections with I > 2 σ ( I ) ; EuBiSe3, orthorhombic, space group P212121, a = 33.307 ( 2 ) A , b = 15.5804 ( 9 ) A , c = 4.2274 ( 2 ) A , V = 2193.7 ( 2 ) A 3 , Z = 16 , R ( F ) = 2.68 % for 183 parameters and 4895 reflections with I > 2 σ ( I ) .