13779-92-5Relevant academic research and scientific papers
The niobium iodides. Characterization of niobium(IV) iodide, niobium(III) iodide, and triniobium octaiodide
Seabaugh, Pyrtle W.,Corbett, John D.
, p. 176 - 181 (1965)
The condensed niobium-niobium(V) iodide system contains three intermediate phases, NbI4, NbI3, and Nb3I8, all qualitatively diamagnetic at room temperature. Niobium tetraiodide is evidently trimorphic. The weakly endothermic α → β transition observed at ca. 348° only on heating is without effect in the powder pattern data. A more substantial β → γ transition occurs at 417°, and γ-NbI4 melts incongruently at 503° to form an iodide-rich liquid and solid Nb3I8. Niobium(III) iodide may be obtained by thermal decomposition of NbI4, as a sublimate from mixtures with Nb3I8, or as the initial product of oxidation of excess metal. The phase is apparently not an equilibrium compound in the system since it decomposes slowly and irreversibly at about 513° into iodide-rich liquid and Nb3I8. The phase in equilibrium with the metal is Nb3I8 (NbI2.67±0.02), which may also be obtained by thermal decomposition of higher iodides or as the phase transported from mixtures with metal. The two lower niobium iodides show only a limited correspondence with those reported in the niobium chloride and bromide and tantalum iodide systems.
No solid solution compounds in between the binaries: Syntheses and crystal structures of Nb(Br0.62(4)Cl0.38(4))2Cl2 and NbI2Cl2
Reckeweg, Olaf,Schleid, Thomas
, p. 29 - 34 (2018)
The anion-mixed niobium tetrahalides Nb(Br0.62(4)Cl0.38(4))2Cl2 and NbI2Cl2 were obtained by heating NbBr5 with NbCl5 and NbI5 with NbCl5, respectively, in equimolar ratios with niobium metal in evacuated, torch-sealed silica ampoules at 720 K for 3 days. The orthorhombic title compounds form as very brittle black needles and were characterized by single-crystal X-ray diffraction [space group: Immm, Z = 4; a = 704.27(6), b = 824.13(7), c = 929.64(8) pm for Nb(Br0.62(4)Cl0.38(4))2Cl2 and a = 753.76(6), b = 829.38(7) and c = 983.41(8) pm for NbI2Cl2]. Surprisingly enough, these mixed-anionic halides are not isostructural with either NbCl4, NbBr4 or NbI4, but crystallize isotypically with TaI2Cl2, thus being examples for differential site occupancy stabilized materials. Structural features of other niobium(IV) halides are compiled and compared to those of Nb(Br0.62(4)Cl0.38(4))2Cl2 and NbI2Cl2. Except for NbF4, they all exhibit chains of trans-edge connected [NbX6]2? octahedra, which allow Peierls distortions to form Nb–Nb single bonds. The packing of these chains differ, however, depending on the actual halide or mixed-halide combination.
Effect of the spin-orbit interaction of ligands on the parameters of EPR spectra for a series of niobium(IV) complexes of trans-[NbX4(OPPh3)2] (X = Cl, Br, I)
Nadolinny, Vladimir A.,Poltarak, Pavel A.,Komarovskikh, Andrey Yu.,Tumanov, Sergey V.,Samsonenko, Denis G.,Komarov, Vladislav Yu.,Syrokvashin, Mikhail M.,Dorovatovskii, Pavel V.,Lazarenko, Vladimir A.,Artemkina, Sofya B.,Fedorov, Vladimir E.
, (2021)
Two crystal modifications of new molecular niobium(IV) complex trans-NbI4(OPPh3)2 were obtained by ampoule synthesis, and their X-ray crystal structures were solved (P-1, a = 9.5795 ?, b = 9.7287 ?, c = 11.2337 ?, α = 107.984°, β = 104.061°, γ = 95.500°, V = 949.24 ?3; P21, a = 10.204 ?, b = 16.039 ?, c = 11.857 ?, β = 102.663°, V = 1893.3 ?3). For the series of molecular complexes trans-NbX4(OPPh3)2 (X = Cl, Br, I) magnetic properties were studied and systematized using EPR, magnetic susceptibility measurements, and theory calculations with DFT approximation. Theory calculations of EPR parameters have shown good accordance with experimental data and allowed to establish a negative sign of the principal hyperfine tensor values.
ELECTRICAL CONDUCTIVITIES OF NIOBIUM IODIDES.
Kawamura,Shirotani,Tachikawa
, p. 233 - 238 (1979)
The temperature and pressure dependences of the electrical resistivities in the single crystals of the niobium iodides, NbI//5, NbI//4 and Nb//3I//8, were measured. The resistivity in ab plane of Nb//3I//8 was 50 OMEGA cm and along the c axis was about 10
Scanning Tunneling and Atomic Force Microscopy Study of Layered Transition Metal Halides Nb3X8 (X=Cl, Br, I)
Magonov, S. N.,Zoennchen, P.,Rotter, H.,Cantow, H.-J.,Thiele, G.,et al.
, p. 2495 - 2503 (2007/10/02)
Niobium halides Nb3X8 (X=Cl, Br, I) are made up of layers of composition Nb3X8, and the two surfaces (A and B) of their individual Nb3X8 layers are not equivalent an atomic corrugations.The surfaces of these halides were examined by atomic force microscopy (AFM) and scanning tunneling microscopy (STM) to obtain atomic resolution images.For a given surfaces, AFM images differ significantly from STM images, and the resolution of the STM images depends on the tunneling conditions.The observed AFM and STM images were analyzed by calculating the total electron density distribution, ρ(rO), and the partial electron density distribution, ρ(rO, ef), for the two surfaces of single Nb3X8 (X=Cl, Br, I) layers.Our work shows that the AFM and STM images are well dscribed by the ρ(rO) and ρ(rO, ef) plots, respectively.A combined use of AFM and STM is useful in characterizing the surfaces of layered materials, and calculations of ρ(rO) and ρ(rO, ef) plots are indispensable in interpreting their AFM and STM images.
Heavier Halides of Early Transition Elements by Halide-exchange Reactions. Crystal and Molecular Structure of2
Calderazzo, Fausto,Pallavicini, Piersandro,Pampaloni, Guido,Zanazzi, Pier Francesco
, p. 2743 - 2746 (2007/10/02)
The decahalogenodimetalates of zirconium(IV) as their triphenylmethyl deivatives have been obtained by the reaction of M(BH4)4 with the appropriate Ph3CX or by addition of Ph3CX to MX4.The crystal and molecular structure of2 h
