Reaction Of Niobium Pentachloride Research Articles

Reaction of Niobium Pentachloride with Sodium Borohydride in Ionic Melts

Reaction of Niobium Pentachloride with Sodium Borohydride in Ionic Melts

Formation of Niobium Diboride Nanoparticles by the Reaction of Niobium Pentachloride with Sodium Borohydride in Ionic Melts of Alkali Metal Halides

Formation of Niobium Diboride Nanoparticles by the Reaction of Niobium Pentachloride with Sodium Borohydride in Ionic Melts of Alkali Metal Halides

Molybdenum(VI) oxide: New methods of synthesis and properties

Objectives. The present study aims to develop new methods for the synthesis of molybdenum(VI) oxide, which is a precursor for the synthesis of functional materials, as well as to investigate the physicochemical properties of the resulting oxide phases. Methods. The synthesized phases and the products of their thermolysis were studied by differential thermal analysis, IR spectroscopy, X-ray diffraction analysis, and granulometry. Results. Three methods for the synthesis of molybdenum(VI) oxide were developed, and the physicochemical properties of the oxide phases obtained were studied. The first method consisted in the reaction of molybdenum pentachloride with a 6.0–9.5 mol/L ammonia solution, the second one was the reaction of niobium pentachloride with a sulfuric acid solution, and the third method involved the reaction of ammonium molybdate with nitric acid, affording brown molybdenum(V) MoO(OH)3 hydroxide, a bright blue precipitate of molybdenum blue MoO2.75, and white hydrated oxide MoO3·H2O, respectively. Conclusions. A series of thermal and X-ray diffraction analysis demonstrated that in all cases the samples were amorphous phases. Heat treatment at 580 °C of the synthesized phases led to the formation of a rhombic modification of molybdenum trioxide. The lattice parameters and X-ray density were calculated for all thermolysis products. The effect of heat treatment on the particle size of the synthesized samples and their thermolysis products was studied. Particle size analysis demonstrated that particles of different diameters were formed depending on the synthetic method. The smallest particle size (0.3–0.6 µm) was found in molybdenum trioxide, a product of the thermolysis of the sample obtained by the reaction of molybdenum pentachloride with a concentrated ammonium solution.

Synthesis, Characterization and Antibacterial Activity of O-Alkyl/O-Aryl trithiophosphate derivatives of Niobium (V)

Monochloro-niobium(V) bis-O-alkyl/O-aryl trithiophosphates, ClNb[ROP(S)SS]2 (where R = Me, Et, Pri, Bui, Ph, CH3-Ph) have been synthesized by the reaction of niobium pentachloride with O-alkyl/O-aryl trithiophosphoric acid in 1: 2 molar ratio, in refluxing ethanol. O-alkyl/O-aryl trithiophosphate derivatives of niobium (V) are pale yellow monomeric solids, soluble in co-ordinating solvents like DMSO, DMF and exhibit high sensitivity towards moisture. The newly synthesized derivatives have been characterized by elemental analysis, molecular weight measurement and spectroscopic (IR, 1H and 31P NMR) studies. On the basis of it is postulated that niobium is in penta-co-ordinated state and new derivatives show trigonal bipyramidal geometry. Two O-alkyl/O-aryl trithiophosphoric acid ligands are co-ordinated to niobium ion as a bidentate ligand chelating via two thiolate S atoms. Each of them forms a four-membered chelate ring.

Physicochemical, quantum mechanical and thermoanalytical investigations of newly synthesized pentakis(2,4-dimethylphenoxo) niobium (V) as potential precursor of Nb2O5

The pentakis(2,4-dimethylphenoxo) niobium (V) complex of composition [Nb(OC6H3(CH3)2-2,4)5] has been synthesized by the reaction of niobium pentachloride with 2,4-dimethylphenol in 1:5 M ratio in CCl4 and characterized by elemental analyses, molar conductivity, molecular weight determination, IR, 1H NMR and mass spectral techniques. The geometrical optimization of the complex has been performed by DFT in SIESTA code using standard conjugate gradient (CG) technique. From bond lengths and bond angles of the optimized structure a trigonal-bipyramidal geometry around niobium has been proposed. The HOMO and LUMO energies were analysed to predict the reactivity of the complex and to evaluate global reactivity descriptors-ionization potential (IP), electron affinity (EA), chemical potential (μ), hardness (η), softness (S), electronegativity (χ) and global electrophilicity index (ω). The molecular orbital contributions have been analysed from the total density of states (TDOS), partial density of states (PDOS) and crystal orbital Hamilton populations (COHPs). The thermal behaviour of the complex studied by TG and DTA techniques has indicated it to decompose in single step yielding Nb2O5 as the decomposition product authenticated by IR spectra. The kinetic and thermodynamic parameters from TG data have been computed using Coats–Redfern and Achar equations and F1 first order random nucleation mechanism has been deduced.

Synthesis, characterization, and acceptor behavior of dichlorotris(2-t-butylphenoxo)niobium(V)

The reaction of niobium pentachloride with three equivalents of 2-t-butylphenol in carbon tetrachloride afforded [NbCl2(OC6H4C(CH3)3-2)3]. The identity of the complex has been established by elemental analyses, molar conductance, molecular weight determination, IR, 1H, and 13C-NMR and UV-Vis spectral studies. Based upon these studies, a square–pyramidal geometry around niobium has been proposed. Thermal behavior of the complex has been studied by TGA and DTA. Acceptor behavior of [NbCl2(OC6H4C(CH3)3-2)3] toward Ph3P, Ph3As, Ph3PO, Ph3AsO, and an uncommon ligand arsenictrithiophenoxide As(SPh)3 allows the isolation of 1 : 1 addition compounds as shown by physicochemical, IR, and 1H-NMR spectral studies. The formation of [NbCl2(OC6H4C(CH3)3-2)3] · As(SPh)3 appears to be the first adduct of its class and suggests the suitability of As(SPh)3 as a ligand.

Dual source APCVD synthesis of TaN and NbN thin films on glass from the reaction of MCl5 (M = Ta, Nb) and 1,1,1,3,3,3-hexamethyldisilazane

Niobium nitride films were synthesised by the reaction of niobium pentachloride and hexamethyldisilazane (NH(SiMe3)2, HMDS) under atmospheric pressure chemical vapour deposition (APCVD) conditions. Films were deposited at 400–580 °C in a cold wall CVD reactor. X-ray photoelectron spectroscopy showed that the films consist of niobium and nitrogen with binding energy shifts of 206.8 eV for Nb 3d and 396.8 eV for N 1s. In a similar manner tantalum pentachloride was reacted with HMDS under APCVD at 400–580 °C to give reflective silver films consisting of tantalum nitride. EDAX analysis showed the presence of tantalum and nitrogen in these films. Both sets of films were hard and chemically inert to common solvents and acids, they were also crystalline at substrate temperatures of 550 °C and above showing the typical cubic NaCl pattern of refractory nitrides (TaN a = 4.34(1) A; NbN a = 4.33(1) A). Raman patterns of the films were somewhat indistinct but matched bulk samples. The films were an aesthetically pleasing silver colour and showed no change in optical properties when stored in air for over two years; the films have potential as decorative reflective coatings.

Reaction of niobium pentachloride with bis(triethylgermyl)cadmium

The reaction of niobium pentachloride with Cd(GeEt3)2 (1 ∶ 1) in THFin vacuo has been studied. The reaction affords Et3GeNbCl4 · THF, which was characterized by elemental analysis and IR spectroscopy. To refine the composition of the compound, the thermolysis of Et3GeNbCl4 · THF at 85 and 180 °C was studied.

Formation Process of Niobium Nitride by the Reaction of Niobium Pentachloride with Ammonia in the Vapor Phase and Properties of the Niobium Nitride Formed

Abstract The reaction products of gaseous NbCl5 with ammonia were NbCl5·5NH3 at 200 °C, NbCl5·5NH3, Nb4N5, and NH4Cl at 250–500 °C, Nb4N5 and NH4Cl at 550–950 °C, δ-NbN and NH4Cl at 1000 °C, δ-NbN, Nb2N, NH4Cl, and HCl at 1100 °C, and δ-NbN, Nb2N, Nb4N3, δ′-NbN, ε-NbN, NH4Cl, and HCl at 1200–1300 °C. In the vapor-phase reaction of gaseous NbCl5 with ammonia, the reaction of gaseous NbCl5 with ammonia to form NbCl5·5NH3 occurs first. Above ca. 235 °C, the NbCl5·5NH3 reacts with ammonia to form Nb4N5. Above ca. 1000 °C, the Nb4N5 decomposes to δ-NbN. Above about 1100 °C, in addition to these reactions, the nitriding of niobium, formed by the reduction of gaseous NbCl5 with the hydrogen resulting from the thermal dissociation of ammonia, also occurs to form Nb2N at 1100 °C and Nb2N, Nb4N3, δ′-NbN, and ε-NbN at 1200–1300 °C. When the Nb4N5, formed by the vapor-phase reaction, is heated in an argon atmosphere, it changes to δ-NbN at ca. 1000 °C, to δ-NbN and ε-NbN at 1100–1200 °C, and then to Nb4N3 and δ-NbN at 1300 °C. The niobium nitrides formed above 1200 °C are uniform, ultrafine powders with particle diameters of the order of 1/100 μm.

Halo-alkoxide complexes of niobium(V) and tantalum(V)

Niobium and tantalum pentachloride and pentabromide react with oxygen donor ligands in anhydrous alcohol to yield halo-alkoxide complexes of the type M(OR) 2C1 3 · L (where M = Nb, Ta; R = CH 3, C 2H 5; X = C1, Br; L = ( C 6 H 5) 3 PO, (C 6H 5) 3AsO, (C 6H 5) 2SO and ((CH 3) 2N) 3PO). NbOCl 3 · 2((CH 3) 2N) 3PO has also been prepared by the reaction of niobium pentachloride with excess of hexamethylphosphoramide in Analar methanol. The preparation of compounds having the general formula M(SC 2H 5) n C1 5− n has been attempted by the reaction of metal(V) chlorides with C 2H 5SH. Some chemical properties, electrical conductivities, melting points, solubilities, IR spectra (4000-200 cm −1) and X-ray powder patterns are reported.

399. Amine compounds of the transition metals. Part II. The reaction of niobium pentachloride with some aliphatic amines

399. Amine compounds of the transition metals. Part II. The reaction of niobium pentachloride with some aliphatic amines

962. Studies on the behaviour of halides of the transition metals with ammonia. Part I. The reaction of niobium pentachloride with ammonia

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