- The preparation, properties, and crystal structures of some scandium sulfides in the range Sc2S3-ScS
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Scandium sesquisulfide, Sc2S3, was prepared by the high-temperature reaction of hydrogen sulfide with scandium sesquioxide. Due to the problem of stoichiometry associated with the high melting point, 1775°, stoichiometric crystals of Sc2S3 were prepared by chemical transport with I2 at 950°. A nonstoichiometric material containing an excess of scandium compared with Sc2S3 was prepared by heating Sc2S3 under vacuum at 1650°. Crystals of ScS were prepared by the reaction of scandium metal with sulfur. The crystal structure of Sc2S3 is closely related to that of NaCl, but the unit cell is twelve times as large due to a complex ordering arrangement of the cation voids. Each octahedron surrounding sulfur has two vertices empty, and the bond angles are all very close to 90°. The nonstoichiometric material has a much simpler structure which is also closely related to that of NaCl, with Sc1.37S2 per rhombohedral unit cell. This structure, in which one cation site is filled and the other is only partially occupied, could exist over the whole range between Sc2S3 and ScS, which was found to have the NaCl structure. Stoichiometric Sc2S3 is a semiconductor with a band gap of about 2 e.V., but the materials between Sc2S3 and ScS are good electrical conductors. Electrical conduction in the latter materials appears to involve a 3d band.
- Dismukes,White
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- A missing rare-earth oxide halide structure now observed for scandium oxide iodide, ScOI
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Single crystals of ScOI were obtained from the residue of a vacuum sublimation of crude ScI3. The colourless plates crystallize with a new structure type: Monoclinic, C2/m, Z = 8, a = 1933.3(6) pm, b = 386.10(8) pm, c = 722.4(2) pm, β = 93.51(3)°, Vm = 538.2(3) cm 3 mol-1. The structure represents a missing link between the YOF/SmSI type variants (CN of the metal ion 4+3, only 36 nets stacked) and the PbFCl and FeOCl structure types (only 44 nets stacked, CN 4+4 and 4+2, respectively). In ScOI there are 44 (Sc, O) and 36 nets (I) stacked such that ScIII has a coordination number of 4+3.
- Zimmermann, Sina,Meyer, Gerd
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- The molecular solid Sc24C10I30: A truncated, hollow T4 supertetrahedron of iodine filled with a T3 supertetrahedron of scandium that encapsulates the adamantoid cluster Sc 4C10
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(Figure Presented) Like a Russian doll: In the nanomolecule Sc 24C10I30, an outer I30 envelope (pink) surrounds a Sc20 T3 supertetrahedron (blue), which is filled by a C10 T2 supertetrahedron (gray), which, in turn, is filled by a Sc4 T1 tetrahedron (light gray), containing two electrons in a four-center, two-electron bond.
- Jongen, Liesbet,Mudring, Anja-Verena,Meyer, Gerd
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- Structural characterization of methanol substituted lanthanum halides
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The first study into the alcohol solvation of lanthanum halide [LaX3] derivatives as a means to lower the processing temperature for the production of the LaBr3 scintillators was undertaken using methanol (MeOH). Initially the de-hydration of {[La(μ-Br)(H2O)7](Br)2}2 (1) was investigated through the simple room temperature dissolution of 1 in MeOH. The mixed solvate monomeric [La(H2O)7(MeOH)2](Br)3 (2) compound was isolated where the La metal center retains its original 9-coordination through the binding of two additional MeOH solvents but necessitates the transfer of the innersphere Br to the outersphere. In an attempt to in situ dry the reaction mixture of 1 in MeOH over CaH2, crystals of [Ca(MeOH)6](Br)2 (3) were isolated. Compound 1 dissolved in MeOH at reflux temperatures led to the isolation of an unusual arrangement identified as the salt derivative {[LaBr2.75·5.25(MeOH)]+0.25 [LaBr3.25·4.75(MeOH)]-0.25} (4). The fully substituted species was ultimately isolated through the dissolution of dried LaBr3 in MeOH forming the 8-coordinated [LaBr3(MeOH)5] (5) complex. It was determined that the concentration of the crystallization solution directed the structure isolated (4 concentrated; 5 dilute) The other LaX3 derivatives were isolated as [(MeOH)4(Cl)2La(μ-Cl)]2 (6) and [La(MeOH)9](I)3·MeOH (7). Beryllium Dome XRD analysis indicated that the bulk material for 5 appear to have multiple solvated species, 6 is consistent with the single crystal, and 7 was too broad to elucidate structural aspects. Multinuclear NMR (139La) indicated that these compounds do not retain their structure in MeOD. TGA/DTA data revealed that the de-solvation temperatures of the MeOH derivatives 4-6 were slightly higher in comparison to their hydrated counterparts.
- Boyle, Timothy J.,Ottley, Leigh Anna M.,Alam, Todd M.,Rodriguez, Mark A.,Yang, Pin,Mcintyre, Sarah K.
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p. 1784 - 1795
(2010/07/03)
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- On the reactivity of lanthanide iodides LnIx (x < 3) formed in the reactions of lanthanide metals with iodine
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The reduced lanthanide iodides of the composition LnIx (Ln = Sc, Y, La, Ce, Pr, Gd, Ho, and Er; x 3) were obtained by the reaction of an excess of the appropriate metal with iodine at high temperatures. The diamagnetism of the Sc, Y, and La d
- Khoroshenkov,Petrovskaya,Fedushkin,Bochkarev
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p. 699 - 702
(2008/10/08)
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- Infrared spectrum of scandium triiodide in benzene solution
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The IR spectrum of scandium triiodide in benzene solution was measured on an IG 983 Perkin-Elmer spectrometer in the range 180-450 cm-1. Bands with maxima at 301, 208, and 225 cm-1 are assigned to dimeric species, and a 265 cm-1 band corresponds to the scandium triiodide monomer.
- Ezhov,Sevast'yanov
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p. 876 - 878
(2007/10/03)
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- The Structure of Monomeric and Dimeric Scandium Triiodide Molecules
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The structures of molecules in the vapor phase over ScI3(s) at 1050 K were studied by gas phase electron diffraction. The vapor contains scandium triiodide dimers (75%) and monomers. The mean internuclear distances (pm) and valence angles (deg) are r(g)(ScI) = 262(2) and α(g)(IScI)= 117(2) in ScI3 and r(g)(ScI1) = 262(3), r(g)(ScI3) (in the ring) = 27 8(3), and α(I1ScI2) = 125(5) in Sc2I6.
- Ezhov, Yu. S.,Komarov, S. A.,Sevast'yanov, V. G.
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p. 1910 - 1912
(2008/10/08)
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- Synthesis, characterization, and crystal structures of two scandium cluster carbides and a boride, Sc7X12C (X = I, Br) and Sc7I12B
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The isomorphous compounds Sc(Sc6I12C) and Sc(Sc6Br12C) have been synthesized, and their structures have been successfully refined in the acentric space group R3 (Z = 3; a = 14.717 (1) ?, c = 9.847 (2) ?, R = 0.045 and a = 13.628 (1) ?, c = 9.203 (1) ?, R = 0.034, respectively). The structure exhibits a significantly asymmetric halogen environment about the isolated scandium atom and a distortion of the cluster from D3d to C3 symmetry. The changes may reflect the operation of an alternative matrix effect arising from the large halide and the small interstitial. The magnetic susceptibility of the iodide is in agreement with the calculated MO description and the assignment of the isolated atom as scandium(III). The analogous iodide boride was synthesized and characterized by X-ray powder data. A passable but erroneous refinement of the iodide carbide in space group R3 as Sc(Sc7I12C2) (R = 0.035) showed some of the same characteristics of earlier structural results for other M7X12Z compositions.
- Dudis, Douglas S.,Corbett, John D.,Hwu, Shiou-Jyh
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p. 3434 - 3438
(2008/10/08)
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