Syntheses and characterization of the cubic uranium chalcogenides Rh2U6S15, Cs2Ti2U6Se15, Cs2Cr2U6Se15, and Cs2Ti2U6Te15

Ward, Matthew D.; Oh, George N.; Mesbah, Adel; Lee, Minseong; Choi, Eun Sang; Ibers, James A.

doi:10.1016/j.jssc.2015.04.005

Cited by 8 publications

(5 citation statements)

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“…The Th−Te distances compare favorably with those in known related thorium tellurides with eight coordinated thorium atoms (Table 4). The Ti−Te distances (2.8040(4)−2.8221(4) Å) in Ba 2 TiUTe 7 can be compared with Ti 2+ −Te distances in the charge balanced Cs 2 Ti 2 U 6 Te 15 (2.787(1) Å) 42 and TiTe (2.730(1) Å) compounds. 43 However, Ti 4+ −Te distances in TiTe 2 (2.770(1) Å), 44 TiZrTe 4 (2.754(1)−2.759(1) Å), 45 Cu 2 TiTe 3 (2.647(1)−2.967(1) Å), 46 and TlCuTiTe 3 (2.678(4)−2.838(4) Å) 47 are close to these Ti 2+ −Te distances where the Ti atom is also octahedrally coordinated.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Three New Quaternary Actinide Chalcogenides Ba₂TiUTe₇, Ba₂CrUTe₇, and Ba₂CrThTe₇: Syntheses, Crystal Structures, Transport Properties, and Theoretical Studies

et al. 2015

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The three new quaternary actinide chalcogenides Ba2TiUTe7, Ba2CrUTe7, and Ba2CrThTe7 have been synthesized. From single-crystal X-ray diffraction studies these isostructural compounds are found to crystallize in a new structure type in space group D2h16–Pnma of the orthorhombic system. The structure features ∞1[MAnTe74–] strips (M = Cr or Ti; An = Th or U) that propagate in the b-direction and are separated by Ba cations. An atoms are coordinated to eight Te atoms in a bicapped trigonal-prismatic geometry while M atoms are octahedrally coordinated to six Te atoms. Sharing of the AnTe8 and MTe6 polyhedra forms ∞1[MAnTe74–] strips. The presence of the infinite linear Te–Te–Te chains in these compounds makes assignment of oxidation states arbitrary. Resistivity measurements and DFT calculations provide further insight into the properties of these compounds.

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Section: ■ Results and Discussionmentioning

confidence: 99%

Three New Quaternary Actinide Chalcogenides Ba₂TiUTe₇, Ba₂CrUTe₇, and Ba₂CrThTe₇: Syntheses, Crystal Structures, Transport Properties, and Theoretical Studies

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“…Some of the latter have been shown to have intriguing magnetic properties, for example Rb 2 Pd 4 U 6 S 17 , 77 CsTiU 3 Te 9 , 42 and Cs 2 Cr 2 U 6 Se 15 . 78 Yet even for these questions remain that can best be settled by polarized neutron diffraction measurements on single crystals. Such measurements may become possible as the dimensions of single crystals needed continue to decrease.…”

Section: Physical and Electronic Propertiesmentioning

confidence: 99%

Overview of the crystal chemistry of the actinide chalcogenides: incorporation of the alkaline-earth elements

2016

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This review focuses on the results of exploratory syntheses of alkaline-earth-metal actinide chalcogenides Ak-An-Q (Ak = Ba, Sr; An = Th, U; Q = S, Se, and Te). About thirty new compounds are described. Although the basic building blocks of their structures are usually AnQ octahedra and AkQ bicapped trigonal prisms, these are combined in diverse ways to afford eleven new structure types. The structures reconfirm the prevailing presence of An in chalcogenides, although some of the compounds discovered are mixed An/An systems, and a few contain only An. The tendency of the chalcogens to form Q-Q bonds is again evident from the presence of S-S single bonds and infinite Te-Te-Te linear chains. The latter possess interatomic distances of lengths greater than that of a Te-Te single bond but less than that of a Te-Te van der Waals interaction. Assignment of formal oxidation states in compounds containing these chains is arbitrary at best. Addition of metal atoms (M) affords quaternary structures, some of which show remarkable flexibility in the positions of the An and M atoms, and in such compounds the nature of the M elements influences directly the dimensionality of the resultant structure. The presence of adventitious oxygen, often from etching of the fused-silica tubes by oxyphilic An elements, results in new quintary compounds that show remarkable structural variations with change of M. The compounds discussed have shown transport and electronic structures that range from metallic-like to semiconducting. We find, with the exception of BaUSe, when comparisons can be made that the values of the calculated band gaps are reasonably close but usually lower than the experimentally derived values. Thus the method used, in particular the HSE functional, has been generally successful on these 5f actinides. This is an important result because in the absence of suitable crystals, and hence experimental measurements, it still may be possible to offer credible predictions of some of the magnetic and electronic properties of the compounds.

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“…The flux growth of several U(V) oxides has been reported from Cs 2 SO 4 , H 3 BO 3 , and ACl (A = alkali metal) flux . The single-crystal synthesis of several U(IV) fluorides has also been reported using UF 4 and a LiCl–ZnCl 2 eutectic flux under argon in a monel alloy reactor. , Furthermore, the flux growth of many reduced uranium chalcogenides using a variety of fluxes including BaS, BaBr 2 /KBr, and CsCl, in sealed tubes, has been reported. − However, the flux synthesis of uranium(IV) oxides presents several further challenges. UO 2 is inert to many solvents, including alkali chloride fluxes such as the one used for the U(IV) fluoride syntheses.…”

Section: Introductionmentioning

confidence: 99%

Flux Synthesis, Structure, Properties, and Theoretical Magnetic Study of Uranium(IV)-Containing A₂USi₆O₁₅ (A = K, Rb) with an Intriguing Green-to-Purple, Crystal-to-Crystal Structural Transition in the K Analogue

et al. 2015

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The flux growth of uranium(IV) oxides presents several challenges, and to the best of our knowledge, only one example has ever been reported. We succeeded in growing two new reduced uranium silicates A2USi6O15 (A = K, Rb) under flux growth conditions in sealed copper tubes. The compounds crystallize in a new structure type with space group C2/c and lattice parameters a = 24.2554(8) Å, b = 7.0916(2) Å, c = 17.0588(6) Å, β = 97.0860(6) ° (K) and a = 24.3902(8) Å, b = 7.1650(2) Å, c = 17.2715(6) Å, β = 96.8600(6) ° (Rb). A2USi6O15 (A = K, Rb) are isocompositional to a previously reported Cs2USi6O15, and the two structures are compared. K2USi6O15 undergoes an interesting crystal-to-crystal structural phase transition at T ≈ 225 K to a triclinic structure, which is accompanied by an intense color change. The magnetic properties of A2USi6O15 (A = K, Rb, Cs) are reported and differ from the magnetism observed in other U(4+) compounds. Calculations are performed on the (UO6)(-8) clusters of K2USi6O15 to study the cause of these unique magnetic properties.

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Syntheses and characterization of the cubic uranium chalcogenides Rh2U6S15, Cs2Ti2U6Se15, Cs2Cr2U6Se15, and Cs2Ti2U6Te15

Cited by 8 publications

References 32 publications

Three New Quaternary Actinide Chalcogenides Ba₂TiUTe₇, Ba₂CrUTe₇, and Ba₂CrThTe₇: Syntheses, Crystal Structures, Transport Properties, and Theoretical Studies

Three New Quaternary Actinide Chalcogenides Ba₂TiUTe₇, Ba₂CrUTe₇, and Ba₂CrThTe₇: Syntheses, Crystal Structures, Transport Properties, and Theoretical Studies

Overview of the crystal chemistry of the actinide chalcogenides: incorporation of the alkaline-earth elements

Flux Synthesis, Structure, Properties, and Theoretical Magnetic Study of Uranium(IV)-Containing A₂USi₆O₁₅ (A = K, Rb) with an Intriguing Green-to-Purple, Crystal-to-Crystal Structural Transition in the K Analogue

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Syntheses and characterization of the cubic uranium chalcogenides Rh2U6S15, Cs2Ti2U6Se15, Cs2Cr2U6Se15, and Cs2Ti2U6Te15

Cited by 8 publications

References 32 publications

Three New Quaternary Actinide Chalcogenides Ba2TiUTe7, Ba2CrUTe7, and Ba2CrThTe7: Syntheses, Crystal Structures, Transport Properties, and Theoretical Studies

Three New Quaternary Actinide Chalcogenides Ba2TiUTe7, Ba2CrUTe7, and Ba2CrThTe7: Syntheses, Crystal Structures, Transport Properties, and Theoretical Studies

Overview of the crystal chemistry of the actinide chalcogenides: incorporation of the alkaline-earth elements

Flux Synthesis, Structure, Properties, and Theoretical Magnetic Study of Uranium(IV)-Containing A2USi6O15 (A = K, Rb) with an Intriguing Green-to-Purple, Crystal-to-Crystal Structural Transition in the K Analogue

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Three New Quaternary Actinide Chalcogenides Ba₂TiUTe₇, Ba₂CrUTe₇, and Ba₂CrThTe₇: Syntheses, Crystal Structures, Transport Properties, and Theoretical Studies

Three New Quaternary Actinide Chalcogenides Ba₂TiUTe₇, Ba₂CrUTe₇, and Ba₂CrThTe₇: Syntheses, Crystal Structures, Transport Properties, and Theoretical Studies

Flux Synthesis, Structure, Properties, and Theoretical Magnetic Study of Uranium(IV)-Containing A₂USi₆O₁₅ (A = K, Rb) with an Intriguing Green-to-Purple, Crystal-to-Crystal Structural Transition in the K Analogue