| 1. |
- Baranov, A. I., et al.
(författare)
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2D metal slabs in new nickel-tin chalcogenides Ni(7-delta)SnQ(2) (Q=Se, Te) : average crystal and electronic structures, chemical bonding and physical properties
- 2004
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Ingår i: Journal of Solid State Chemistry. - : Elsevier BV. - 0022-4596 .- 1095-726X. ; 177:10, s. 3616-3625
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Tidskriftsartikel (refereegranskat)abstract
- A systematic search for mixed low-valence, nickel-tin chalcogenides performed by establishing phase relations in the parts of Ni-Sn-Se and Ni-Sn-Te ternary systems resulted in the discovery of two new compounds, Ni5.62SnSe2 and Ni5.78SnTe2 Single crystals of both compounds were prepared by chemical transport with iodine and crystal structures were determined by single crystal X-ray investigation. The ED patterns for Ni5.78SnTe2 showed the presence of satellite reflections, which indicate a modulated structure with qapproximate to0.4a*. Average crystal structures of both compounds were determined to be of tetragonal symmetry (Sp.gr.I4/mmm, Z = 2) with a = 3.6890(8) Angstrom, c = 18.648(3) Angstrom, R-w = 0.0716 and a = 3.7680(5) Angstrom, c = 19.419(4) Angstrom, R-w, 0.0832, correspondingly, and are isostructural to known Ni5.72SbSe2 and Ni5.66SbTe2. Measurements were carried out for both compounds with respect to thermal, electrical and magnetic properties. Ab initio band structure calculations were also performed to take a first glance into the electronic structure of such type compounds. The anisotropy of their band structure was found. Physical property measurements showed both compounds to be the anisotropic metallic conductors and paramagnetics. Calculated difference charge density maps revealed pairwise covalent and multicenter metallic nature of the d-metal-chalcogen and d-metal-p-metal interactions, respectively.
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| 2. |
- Baranov, A. I., et al.
(författare)
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Unique (infinity Ni8Bi8S)-Ni-1 metallic wires in a novel quasi-1D compound. Synthesis, crystal and electronic structure, and properties of Ni8Bi8SI
- 2001
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Ingår i: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 0002-7863 .- 1520-5126. ; 123:49, s. 12375-12379
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Tidskriftsartikel (refereegranskat)abstract
- A new quasi-one-dimensional compound Ni8Bi8SI has been synthesized and its crystal structure determined from single-crystal X-ray diffraction data. The structure of Ni8Bi8SI consists of [(infinityNi8Bi8S)-Ni-1] columns separated by iodine atoms. Conductivity and magnetic susceptibility measurements (down to 4.2 K) show that Ni8Bi8SI is a one-dimensional metal and exhibits Pauli paramagnetic properties. These observations are in good agreement with the results from electronic structure calculations. An analysis of the chemical bonding employing difference electron charge density maps reveals strong multicenter Ni-Bi bonds and pair Ni-S interactions within the [(infinityNi8Bi8S)-Ni-1] columns. Only electrostatic interactions are inferred between the columns and iodine atoms.
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| 3. |
- Baranov, A. I., et al.
(författare)
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New metal-rich sulfides Ni6SnS2 and Ni9Sn2S2 with a 2D metal framework : Synthesis, crystal structure, and bonding
- 2003
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Ingår i: Inorganic Chemistry. - : American Chemical Society (ACS). - 0020-1669 .- 1520-510X. ; 42:21, s. 6667-6672
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Tidskriftsartikel (refereegranskat)abstract
- Two new, metal-rich nickel-tin sulfides Ni6SnS2 and Ni9Sn2S2 were found by establishing phase relations in the ternary Ni-Sn-S system at 540 degreesC. Their single crystals were prepared by means of chemical vapor transport reactions. Single crystal X-ray diffraction was used for the determination of their crystal structures. Both compounds crystallize in a tetragonal system (/4/mmm, No. 139, Z = 2, a = 3.646(1) Angstrom, c = 18.151(8) Angstrom for Ni6SnS2, and a = 3.678(1) Angstrom, c = 25.527(8) Angstrom for Ni9Sn2S2). Their crystal structures represent a new structure type and can be considered as assembled from bimetallic nickel-tin and nickel-sulfide slabs alternating along the crystallographic c axis. DFT band structure calculations showed the bonding within the bimetallic slabs to have a delocalized, multicenter nature, typical for metallic systems, and predominantly classical, pairwise bonding between nickel and sulfur.
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| 4. |
- Baranov, A. I., et al.
(författare)
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Quasi-1D cations (1)(infinity) Ni8Bi8S (n+) of variable charge : Infinite columns (1)(infinity) Ni8Bi8S (2+) in the novel compound Ni(8)Bi(8)Sl(2)
- 2003
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Ingår i: Inorganic Chemistry. - : American Chemical Society (ACS). - 0020-1669 .- 1520-510X. ; 42:13, s. 3988-3993
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Tidskriftsartikel (refereegranskat)abstract
- The new compound Ni(8)Bi(8)Sl(2) has been synthesized and its crystal structure determined by X-ray crystallography. The structure contains one-dimensional (1D) cations (1)(infinity)[Ni8Bi8S](2+) separated by iodine anions. The geometry of the columns is similar to that of the recently reported (1)(infinity)[Ni8Bi8S](+), and the main difference between them is only their formal charge. Electronic structure calculations and physical properties measurements were performed to analyze the influence of the number of valence electrons on the bonding and properties of compounds containing these 1D cations. It was shown that the removal of one electron (i.e., (1)(infinity)[Ni8Bi8S](+) --> (1)(infinity)[Ni8Bi8S](2+)) mainly affects the Ni-S bonding within the cation and essentially has no influence on the intermetallic Ni-Bi bonding. It was found that Ni(8)Bi(8)Sl(2) containing double-charged columns has conductivity properties more similar to a pure 1D metal than the congener Ni(8)Bi(8)Sl containing mono-charged columns.
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| 5. |
- Filatova, T. G., et al.
(författare)
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Electronic structure, galvanomagnetic and magnetic properties of the bismuth subhalides Bi4I4 and Bi4Br4
- 2007
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Ingår i: Journal of Solid State Chemistry. - : Elsevier BV. - 0022-4596 .- 1095-726X. ; 180:3, s. 1103-1109
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Tidskriftsartikel (refereegranskat)abstract
- Two bismuth-rich subhalides, Bi4Br4 and Bi4I4, featuring extended quasi one-dimensional metallic fragments in their structures, have been investigated. The gas-phase technique of crystal growth has been refined for obtaining large (up to 5 mm long) single crystals. Electronic structure calculations on three-dimensional structures of both compounds have been performed (DFT level, hybrid B3LYP functional), predicting a semiconducting behavior for both compounds, with an indication of possible directional anisotropy of electric conductivity. Galvanomagnetic (resistance, magnetoresistance, Hall effect, thermopower) and magnetic (temperature and field dependence of magnetization) properties have been measured experimentally. Both compounds are found to be diamagnetic, room-temperature semiconductors with n-type conductivity. While Bi4Br4 demonstrates a typical case of one dimensionality, the difference in magnetoresistivity between Bi4Br4 and Bi4I4 indicates some weak interactions between isolated bismuth metallic fragments within the bismuth substructures.
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| 6. |
- Lyubimtsev, A. L., et al.
(författare)
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The structure and bonding of Ni3Sn
- 2002
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Ingår i: Journal of Alloys and Compounds. - 0925-8388 .- 1873-4669. ; 340:02-jan, s. 167-172
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Tidskriftsartikel (refereegranskat)abstract
- The electronic structure of Ni3Sn was calculated at ab initio levels for the crystal structure of the low-temperature modification of Ni3Sn refined upon data of single-crystal X-ray diffractometry (P6(3)/mmc, a=5.2950(7), c=4.247(1) Angstrom R=0.0288). The calculations were made with the use of fixed Gaussian (CRYSTAL98 software) and energy-dependent (Stuttgart TB-LMTO-ASA software) basis sets. Difference electron charge density maps were analysed and compared with that of a hypothetical hcp Ni in order to understand bonding in Ni3Sn. It was found that bonding in Ni3Sn has multicentre character with Ni-Sn interaction stronger than Ni-Ni one.
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| 7. |
- Isaeva, Anna A., et al.
(författare)
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New metal-rich mixed chalcogenides with intergrowth structures : Ni8.21Ge2S2 and Ni8.45Ge2Se2
- 2009
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Ingår i: Solid State Sciences. - : Elsevier BV. - 1293-2558 .- 1873-3085. ; 11:6, s. 1071-1076
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Tidskriftsartikel (refereegranskat)abstract
- New metal-rich mixed nickel germanium chalcogenides, Ni8.21(1)Ge2S2 and Ni8.45(1)Ge2Se2, were synthesized by a high-temperature ceramic technique. Ni8.21Ge2S2 decomposes incongruently at 798(5) degrees C, while Ni8.45Ge2Se2 is stable only between approximately 600(5) degrees C and 813(5) degrees C. Single crystals were grown from a molten flux and by a recrystallization of presynthesized charge. The X-ray diffraction study revealed that Ni8.21Ge2S2 and Ni8.45Ge2S2 are isostructural and crystallize in the tetragonal system (space group 14/mmm, Z = 2) with a = 3.578(1) angstrom, c = 24.687(5) angstrom, and a = 3.601 (1) angstrom, c = 25.427(6) angstrom, respectively. Their crystal structures comprise heterometallic (2)(infinity) [Ni6Ge2] slabs and are closely related to the Ni8.54Ga2Se2 and Ni8.93Sn2S2 structure types. The geometrical changes of structural units upon p-element substitution in all known Ni(10-delta)E(2)Q(2) (E = element of group 13 or 14; Q = chalcogen) compounds are discussed. The relation to the intergrowth structure of Ni5.46GeSe2 is analyzed.
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| 8. |
- Johansson, A., et al.
(författare)
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The solution thermolysis approach to molybdenum(V) alkoxides : synthesis, solid state and solution structures of the bimetallic alkoxides of molybdenum(V) and niobium(V), tantalum(V) and tungsten(VI)
- 2000
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Ingår i: Journal of the Chemical Society-Dalton Transactions. - : Royal Society of Chemistry (RSC). - 0300-9246 .- 1470-479X .- 1364-5447. ; :3, s. 387-394
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Tidskriftsartikel (refereegranskat)abstract
- No complex formation can be observed between molybdenum(VI) oxoalkoxides and the alkoxides of niobium(V) or tantalum(V) at room temperature. The bimetallic derivatives of molybdenum(V), Mo4M2O8((OPr)-Pr-i)(14), where M=Nb 1 and Ta 2, were instead isolated on cooling from the solutions of the isopropoxides in toluene subjected to a short-time reflux. The X-ray single crystal study showed both 1 and 2 to be built of ((PrO)-Pr-i)(3)M(mu-(OPr)-Pr-i)(3)MoO(mu-O)(2)MoO(mu-(OPr)-Pr-i)(2)MoO(mu-O)(2)MoO(mu-(OPr)-Pr-i)(3)M((OPr)-Pr-i)(3) non-linear chain molecules with 2 Mo-Mo bonds (2.5836(8) Angstrom) and short but non-bonding Mo-M distances (3.1791(8) Angstrom for 1 and 3.1746(8) Angstrom for 2). According to NMR and EXAFS data this structure becomes very fluxional or might even be partially broken into homometallic components in hydrocarbon solutions. The oxidation of 2 with traces of oxygen leads to the formation of Mo3Ta2O8((OPr)-Pr-i)(10) 3. Compound 3 can be isolated in a pure form from the reaction of MoO((OPr)-Pr-i)(4) with Ta((OPr)-Pr-i)(4)(OMe) 6: the presence of methoxide ligands leads to the formation of additional oxoligands via non-reductive thermolysis leading to the formation of a (CH3)(2)C(OMe)(2) ketal as organic byproduct. The molecules of 3 are 5-member rings with a MoO(mu-O)(2)MoO fragment in the basis (Mo-Mo 2.5730(13) Angstrom), coupled to two (mu-(OPr)-Pr-i)(2)Ta((OPr)-Pr-i)(3) fragments that are joined together by an oxomolybdate ligand (mu-O)(2)MoO2. According to NMR-spectroscopic data the aggregate is preserved and rigid in solution. Mo4Ta4O16((OPr)-Pr-i)(12) 4 was found to be one of the products of complete oxidation of 2 (and 3) on prolonged contact with dry oxygen. The thermal treatment of the solutions of MoO((OPr)-Pr-i)(4) and WO((OPr)-Pr-i)(4) in toluene yields (Mo4O8)-O-V(Mo,W)O-VI(2)2((OPr)-Pr-i)(12) 5 with a molecular structure very close to its homometallic analog Mo6O10((OPr)-Pr-i)(12). The complete X-ray single crystal study was carried out for the sample of 5 with (Mo4O8)-O-V(Mo0.45W0.55)O-VI(2)2((OPr)-Pr-i)(12) composition.
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| 9. |
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| 10. |
- Lindsjö, Martin, et al.
(författare)
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Novel Compounds Sn14In10P22I8 and Sn14In10P21.2I8 with Clathrate-I Structure: Synthesis and Crystal and Electronic Structure
- 2001
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Ingår i: Journal of Solid State Chemistry. - : Elsevier BV. - 0022-4596 .- 1095-726X. ; 161:2, s. 232-242
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Tidskriftsartikel (refereegranskat)abstract
- Two new supramolecular pnictidehalides Sn10In14P22I8 (I) anti Sn14In10P21.2I8 (II) have been synthesized using a standard ampoule technique. Both compounds possess the clathrate I type of structure. I crystallizes in the cubic space group Pm (3) over barn (No. 223) with the unit cell parameter a = 11.0450(7) (Z = 1) while II reveals a complicated superstructure (space group P4(2)/m (No. 84), a = 24.745(3) Angstrom, c = 11.067(1) Angstrom, Z = 5) resulting from the partial ordering of vacancies at phosphorus sites. The crystal structures have been solved based on single-crystal X-ray diffraction data sets (omega -2 theta) scans, least-squares refinement against F-2) to R = 0.0376 (Sn10In14P22I8) and R = 0.0569 (Sn14In10P21.2I8). In both structures metal anti phosphorus atoms form a cationic clathrate I framework hosting iodine atoms in the cavities. The composition of both phases complies with the Zintl-Klemm formalism which justifies the existence of vacancies in the structure of II. The Sn-119 Mossbauer spectroscopy data together with the results of the band structure calculations suggest that the electron density on tin atoms is reduced in favor of bands, which lie just below the Fermi level and must define electronic properties of the compounds in question. The differences in the crystal and electronic structures of the cationic tin clathrates are discussed.
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