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Abstract: The three new framework Rb uranyl phosphates and arsenates with anionic parts based on different type of polymeric anions have been prepared by high-temperature solid-state reactions: Rb4[(UO2)6(P2O7)4(H2O)] (1), Rb2[(UO2)3(P2O7)(P4O12)] (2), Rb[(UO2)2(As3O10)] (3). The crystal structures of the synthesized compounds have been solved by direct methods: 1—monoclinic P21/c, a=9.672(1)Å, b=12.951(1)Å, c=32.231(3)Å, β=90.116(4)°, V=4037.3(6)Å3, Z=4, R 1=0.0926 for 6351 unique reflections with ; 2—monoclinic, P21/c, a=6.791(1)Å, b=16.155(3)Å, c=19.856(4)Å, β=97.48(5)°, V=2159.8(7)Å3, Z=4, R 1=0.0286 for 3617 unique reflections with ; 3—orthorhombic, Pbcn, a=10.558(1)Å, b=11.037(1)Å, c=11.464(1)Å, V=1335.9(2)Å3, Z=4, R 1=0.0489 for 1384 unique reflections with . The structures of title are compounds based on 3D negatively charged frameworks with chemical compositions [(UO2)6(P2O7)4(H2O)]4− in 1, [(UO2)3(P2O7)(P4O12)]2− in 2 and [(UO2)2(As3O10)]− in 3. These negative charges are compensated by rubidium cations which are in the channels of 1 and closed cages in structures of 2 and 3. The channels in 1 are directed along the a direction and have minimum dimensions ∼5Å×6Å. This is the first example of porosity generation through solid state synthesis in uranyl compounds. For the first time in uranium chemistry polymeric anionic groups P4O12 and As3O10 were observed in structure of 2 and 3. [Copyright &y& Elsevier]

Presents a study on the structural principles for minerals and inorganic compounds containing anion-centered tetrahedra. Methodology of the study; Results and discussion; Conclusion.

Dark-green platy crystals of the new compound Pb31O22Br10Cl8 (1) have been obtained by rapid quenching of a lead oxide halide melt. The structure of 1 (triclinic, P..., a = 12.1192(7) Å, b = 16.2489(10) Å, c = 18.3007(11) Å, α = 93.104(2)°, β = 95.809(2)°, γ = 111.252(1)°, V= 3325.4(3) ų, Z= 2) can be viewed as incorporation of [PbX6]4- halide units (X = Br, Cl) into the defect PbO matrix. The latter represents a two-dimensional [022- Pb30]16+ cationic layer of OPb4 tetrahedra that can be derived from the [OPb] tetrahedral layer observed in tetragonal PbO. The layer consists of 22 symmetrically inequivalent OPb4 tetrahedra and represents the topologically most complicated arrangement of tetrahedra known to date. [ABSTRACT FROM AUTHOR]

This article presents a study on the chemical structure of highly porous uranyl selenate nanotubules, (C4H12N)14[(UO2)10(SeO4)17(H2O)]. The yellow transparent crystals of these nanotubules were obtained in the room-temperature reaction of uranyl nitrate, butylamine, and H2SeO4 in aqueous solution. The crystals were found to be of quality and size suitable for an X-ray diffraction data collection.

Yakovenchukite-(Y), K3NaCaY2[Si12O30](H2O)4, is a new REE silicate found in a thin (3-4 cm) sodalite-aegirine-microcline veinlet cutting ijolite-urtite at Mt. Kukisvumchorr, Khibiny alkaline massif, Kola Peninsula, Russia. The mineral occurs as small prismatic crystals in intimate association with microcline, aegirine, calcite, catapleiite, donnayite-(Y), fluorapophyllite, fluorite, galena, lead, litharge, molybdenite, natrolite-gonnardite, pyrochlore, rinkite, strontianite, and vuorijarvite-K. Yakovenchukite-(Y) is creamy to colorless, with vitreous luster. The streak is white. The mineral is transparent, non-fluorescent. The Mohs hardness is about 5. The mineral is brittle. Cleavage is perfect on {100}, distinct on {010}, fracture is stepped. Densities are 2.83 g/cm³ (measured by sink/float in heavy liquids) and 2.72 g/cm³ (calculated). Yakovenchukite-(Y) is biaxial (+): nα = 1.520(5), nβ = 1.525(5), nγ = 1.538(5) (589 nm), 2V(meas.) = 60 ± 5°, 2V(calc.) = 61.86°. The optical orientation is Y = c, X = a, Z = b, pleochroism is not observed. Chemical analysis by electron microprobe (wt%): Na2O 4.32, K2O 10.73, CaO 3.42, Y2O3 15.49, Ce2O3 0.10, Dy2O3 0.68, Er2O3 0.88, Tm2O3 0.18, Yb2OE 1.53, ThO2 0.62, SiO2 57.55, H2O (by the Penfield method) 4.70, total 100.20. The empirical formula (based on Si = 12 apfu) is (K2.85 Na0.15)Σ3.00Na1.00 (Ca0.71 Na0.60)Σ1.31 (Y1.72 Yb0.10 Er0.06 Dy0.05 Th0.03 Ce0.01 Tm0.01 Ca0.05)Σ2.03 [Si12 O30.02]⋅3.27H2O. According to single-crystal X-ray study yakovenchukite-(Y) is orthorhombic, Pcca, a = 14.972(8), b = 14.137(7), c = 14.594(8) Å, V = 3089(3) ų, Z = 4. The strongest lines of the X-ray powder diffraction pattern are [dbs(Å) (Iobs) (hkl)]: 7.00 (40) (020), 6.57 (60) (102), 4.20 (50) (222), 3.337 (100) (331), 3.248 (90) (024), 3.101 (40) (142), 3.014 (80) (422), 2.608 (40) (404). The crystal structure of yakovenchukite-(Y) belongs to a new structure type of minerals and inorganic compounds. It is based on microporous octahedral-tetrahedral framework of SiO4-tetrahedra and YO6-octahedra. Silicate tetrahedra share corners to form unprecedented [Si12O30] sheets consisting of 4-, 6-, and 14-membered rings. The sheets are parallel to (001) and are linked into 3D framework through YO6 octahedra. Ca2+, K+, and Na+ cations are located within the framework cavities. The octahedral- tetrahedral framework possess channels extended along the a axis. The channel dimensions are 4.9 x 6.2 Å, which means the free crystallographic diameter of 2.2 x 3.5 Å, that allows classifying yakovenchukite-(Y) as a microporous material. Yakovenchukite-(Y) is the latest low-temperature hydrothermal mineral, formed by alteration of earlier REE-rich minerals (pyrochlore, rinkite, etc.). The mineral is named in honor of Victor N. Yakovenchuk, a mineralogist at the Geological Institute of the Kola Science Centre of the Russian Academy of Sciences, for his outstanding contribution to the mineralogy of alkaline and alkaline-ultrabasic massifs. [ABSTRACT FROM AUTHOR]

Abstract: Single crystals of Cs2(UO2)(CrO4)2 and Rb2(UO2)(CrO4)2 were prepared by solid state reactions. The structures are based upon the [(UO2)(CrO4)2]2− chains. Within the chains, UrO5 pentagonal bipyramids (Ur=uranyl) form Ur 2O8 dimers, which are linked via CrO4 tetrahedra into one-dimensional chains. The CrO4 tetrahedra coordinate uranyl ions in both mono- and bidentate fashion, which is unusual for uranyl chromates. The bidentate coordination has a strong influence upon geometrical parameters of both U and Cr coordination polyhedra. The conformation of the chains in 1 and 2 is different due to the different size of the Cs+ and Rb+ cations. [Copyright &y& Elsevier]

K[AsW2O9], prepared by high-temperature solid-state reaction, is the first member of the arsenate–tungsten bronze family. The structure of K[AsW2O9] is based on a 3-dimensional (3D) oxotungstate–arsenate framework with the non-centrosymmetric P212121 space group, a=4.9747(3)Å, b=9.1780(8) Å, c=16.681(2) Å. The material was characterized using X-ray diffraction, scanning electron microscopy (SEM), differential scanning calorimetry (DSC), Raman and infrared (IR) spectroscopic techniques. The results of DSC demonstrate that this phase is stable up to 1076K. Second harmonic generation (SHG) measurements performed on a powder sample demonstrate noticeable (0.1 of LiIO3) non-linear optical (NLO) activity. [ABSTRACT FROM AUTHOR]

Single crystals of the new compound Pb7O6Br2 are prepared by solid state reaction of PbBr2 and α-PbO (Pt crucible, 750 °C, 1 h). [ABSTRACT FROM AUTHOR]