Search

Pleysteinite, [(H 2 O) 0.5 K 0.5 ] 2 Mn 2 Al 3 (PO 4) 4 F 2 (H 2 O) 10 ⚫ 4H 2 O, is the aluminium analogue of benyacarite, from the Hagendorf-Süd pegmatite, Oberpfalz, Bavaria, Germany. It was found in specimens of altered zwieselite, in association with nordgauite, fluellite, rockbridgeite, pyrite and columbite. Pleysteinite occurs as isolated and small aggregates of colourless, stubby prisms that are typically 10 to 30 µ m wide and up to 100 µ m long. The crystals are flattened on {010} and bounded by {111} , {100} and {001} planes. The calculated density is 2.34 g cm -3. Optically, pleysteinite crystals are biaxial (+), with α=1.566(2) , β=1.580(2) , γ=1.600(2) (measured in white light) and 2 V (meas.) = 80(1) ∘. The empirical formula from electron microprobe analyses and structure refinement is [(H 2 O) 0.50 K 0.50 ] 2 (Mn 1.20 Mg 0.49 Fe 0.272+ Zn 0.05) ∑2.01 (Al 1.63 Fe 0.203+ Ti 0.194+) ∑2.02 (Al 0.56 Ti 0.444+) (PO 4) 4.02 [F 0.58 O 0.31 (OH) 0.11 ] 2 (H 2 O) 10 ⚫ 3.92H 2 O. Pleysteinite has orthorhombic symmetry, with space group Pbca and unit-cell parameters a = 10.4133(8) Å, b=20.5242(17) Å, c=12.2651(13) Å, V=2621.4(4) Å 3 and Z=4. The crystal structure was refined using single-crystal data to wR obs=0.054 for 1692 reflections with I>3σ(I). The crystal structure contains corner-connected linear trimers of Al-centred octahedra that share corners with PO 4 tetrahedra to form 10-member rings parallel to (010). K + cations and water molecules are located in the rings. Additional corner-sharing of the PO 4 tetrahedra with Mn(H 2 O) 4 O 2 octahedra occurs along [010] to complete the 3D framework structure. [ABSTRACT FROM AUTHOR]

Whiteite-(CaMnFe), CaMn 2+ Fe 22+ Al 2 (PO 4) 4 (OH) 2 ⋅ 8H 2 O, is a new whiteite-subgroup member of the jahnsite group from the Hagendorf-Süd pegmatite, Oberpfalz, Bavaria, Germany. It was found in vugs in an altered feldspar area of a specimen composed predominantly of rockbridgeite, with hureaulite and relic triphylite. Other associated minerals in small vugs in the specimen were strengite and laueite. Whiteite-(CaMnFe) occurs as sprays and clusters of colourless to pale yellow, rod-like crystals, with diameters of typically 10 to 50 µ m and lengths up to ∼ 500 µ m. The crystals are flattened on {001} and elongated along [010]. The measured density is 2.80(2) g cm -3. Optically, whiteite-(CaMnFe) crystals are biaxial (+), with α=1.608(3) , β=1.612(3) , γ=1.624(3) and 2 V (meas.) = 59(1) ∘. The empirical formula from electron microprobe analyses and structure refinement is (Ca 0.70 Mn 0.30)Mn(Fe 1.232+ Mn 0.49 Mg 0.29 Zn 0.06) (Al 1.88 Fe 0.123+)(PO 4) 3.96 (OH) 2 (H 2 O) 8. Whiteite-(CaMnFe) is monoclinic, P2 /a , a=14.925(5) , b=7.0100(14) , c=10.053(2) Å, β=111.31(2) ∘ , V=979.9(4) Å 3 and Z=2. The crystal structure was refined using single-crystal data to wRobs=0.052 for 1613 reflections with I>3σ(I). Site occupancy refinements confirm the ordering of dominant Ca, Mn and Fe 2+ in the X , M 1 and M 2 sites, respectively, of the general jahnsite-group formula XM 1 M 2 2 M 3 2 (H 2 O) 8 (OH) 2 (PO 4) 4. [ABSTRACT FROM AUTHOR]

The conformational behavior of benzoylureas is examined by using the NMR, IR, X-ray and computational analysis. The analysis has highlighted the propensity for benzoylureas to switch conformation that has depended on the environment of the molecule for a particular set of substituents.

In this article, we build upon our recent efforts that have focused on demonstrating the value of microwave-assisted synthesis in polyoxometalate (POM) chemistry. Herein, we report for the first time a microwave-assisted approach that enabled the facile preparation and crystallization of a large POMcontaining coordination complex. The judicious selection and reaction of a sparingly water-soluble transition-metal-substituted polyanion (TMSP) salt with the tritopic ligand 2,4,6-tris(4-pyridyl)-1,3,5-triazine (TPT) in a mixed solvent system under moderately forcing conditions yields Ba9[(BIIIWVI 11O39CoIII)3-(C18H12N6)]·38H2O in moderate yield. Crystallographic analysis reveals significant intermolecular interactions between the organic ligand and neighbouring polyanions, predominantly C-H…O(water) in nature; meanwhile, the solvated regions of the crystal show significant disorder. To supplement the crystallographic study, combustion analysis, and IR and 1H NMR spectroscopic analyses were conducted, revealing good bulk purity and the stability of the complex in aqueous media. [ABSTRACT FROM AUTHOR]

The crystal structure of ramdohrite, Pb5.9Fe0.1Mn0.1In0.1Cd0.2Ag2.8Sb10.8S24, from the Chocaya mine, Potosí, Bolivia, determined by Makovicky and Mumme from film data in 1983, was refined from single-crystal diffractometer data to the R value 0.060, based on 5230 reflections [I > 2σ(I)] from a twinned crystal. Lattice parameters are a = 8.7348(3), b = 13.0543(4), c = 19.3117(6) Å, and β = 90.179(2)°, space group P21/n. Two bicapped trigonal prismatic sites of lead bridge and unite adjacent (311) PbS slabs. These slabs contain five distinct coordination pyramids of Sb with trapezoidal cross sections, a mixed and disordered Sb-Ag-Cd-(Pb) site, refined as 0.39 Sb + 0.61 Ag, a pure Ag site with a very open, irregular tetrahedral coordination, and an octahedral site occupied by Pb. The (311)PbS slabs contain large lone electron pair micelles formed by four distinct antimony sites in alternation with small such micelles formed by a single Sb site. The geometric arrangement of these slabs is not based on crankshaft chains of short, strong Me-S bonds but on a chess-board arrangement of (predominantly) Sb pairs that share two common S atoms via short bonds. Relationships to, and differenced from, fizelyite and uchucchacuaite are described and discussed. [ABSTRACT FROM AUTHOR]

The mol­ecule of the title compound, tetra-μ2-acetato-diaquadi-μ2-chloro-tetra­chloro­tetra­kis[μ4-3-hydroxy-2,2-bis­(oxido­meth­yl)propanol­ato]­tetra­methanoldi-μ3-methanolato-di-μ5-oxo-octa­manganese(II)­tetra­manganese(III), [Mn4IIIMn8II(CH3O)2(C2H3O2)4(C5H9O4)4Cl6O2(CH4O)4(H2O)2], displays a centre of symmetry. The structure of the {Mn4IIIMn8IIO18Cl2}10− core is composed of three layers and features two oxo ligands binding in a rare μ5-mode. [ABSTRACT FROM AUTHOR]