13478-45-0Relevant articles and documents
Triniobiumoctabromide, Nb3Br8, revisited
Habermehl, Katja,Meyer, Gerd
, p. 770 - 772 (2010)
A facile route to single crystals of Nb3Br8 by the reaction of NbBr5 with the wall of the niobium reaction vessel at 800 °C is reported. The crystal structure (a = 707.87(5), c = 3895.7(6) pm, R3m, Z = 6) was determined from diffractometer data; the crystal data are compared with those obtained from film data in 1966 which were of already high precision. Triangular {Nb3} clusters with Nb-Nb distances of 288.6(2) pm are surrounded by 13 bromide ligands which bridge them to double layers, {Nb3}(μ3-Br4)i 1/1(μ 2-Br1)i (3/2)·2(μ1-Br2) a-a 6/2(μ1-Br3)a-a-a 3/3 that are stacked to a 12R structure.
Studies on interactions in the NbBr5-Nb system
Vlaskina,Izmailovich,Tsirelnikov
, p. 85 - 90 (1996)
For studying the thermal disproportionation and interaction processes of niobium bromides in the NbBr5-Nb system thermoanalytical and tensimetric methods were employed. The study revealed that the reduction of niobium pentabromide by metallic n
Mehrotra, R. C.,Kapoor, P. N.
, p. 348 - 353 (1966)
The preparation and properties of niobium(IV) compounds. I. Some niobium(IV) halides and their pyridine adducts
McCarley, Robert E.,Torp, Bruce A.
, p. 540 - 546 (1963)
Reaction of NbBr5 and niobium metal in a sealed tube under a temperature gradient from 410 to 350° gave NbBr4 in good yields. However, an increase in the higher temperature from 410 to 450° was sufficient to eliminate NbBr4 as a product and cause deposition of a lower bromide. The halides NbCl4 and NbBr4 are isomorphous solids of orthorhombic structure and lattice constants a = 8.12, b = 8.88, c = 6.84 A?. and a = 8.60, b = 9.31, c = 7.19 A?., respectively; both solids are diamagnetic over the range -195 to 25°. Formation of the tetrahalodi-(pyridine)-niobium(IV) complexes resulted from the reactions of the pure tetrahalides (Cl, Br, I) with pyridine at room temperature; at elevated temperatures a second form of NbBr4(py)2 crystallized from pyridine. Evidence bearing on the structure of the pyridine adducts was obtained from conductance, spectral, and magnetic susceptibility measurements. The complexes are paramagnetic and exhibit moments much lower than the spin-only value for one magnetic electron; the spectra of solutions in pyridine show intense bands in the visible region which have been attributed to charge transfer transitions.
Rolsten, R. F.
, p. 126 - 127 (1958)
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.
