Transition metal nitrides preparation

Azuma et al. have studied the electrochemical properties of transition metal nitrides prepared by a reactive radio-frequency sputtering method such as ZrN [22], NbN [23], CoN [24], TiN, and VN [23]. Electrochemical reduction of oxygen was... 

This paper consists of three parts. The first part describes the high pressure synthesis of bimetallic compounds of NbN and MN where M is a Group 13 metal such as Al, Ga, or In. The second part discusses crystal structure investigations of a series of alkaline earth and transition metal nitrides, carried out to understand the bonding surrounding the transition metals. The third part describes the preparation of new metastable transition metal nitride and their solid solutions by rf-sputter deposition. 

Conventional preparation methods of transition metal nitrides usually involve the direct reaction between a nitriding gas (NH3, N2) and a solid... 

Transition metal nitrides can be prepared by allowing the metal or the metal hydride in powdered or compact form to react with molecular or atomic nitrogen or flowing ammonia ... 

Chen JG (1996) Carbide and nitride overlayers on early transition metal surfaces preparation, characterization, and reactivities. Chem Rev 96 1477... 

Transition metal nitrides can be prepared easily by nitridation of metals, oxides, and other precursors containing the transition metal (e.g. sodium or ammonium salts) ... 

Figure 5.10 Preparation of transition metal nitride nanoparticles using nanoporous C3N4 matrix.

Different methods have been discussed for the preparation of transition metal nitride and carbide nanoparticles, including state-of-the-art procedures and more recently reported methods. 

Diffusion layers of transition metal nitrides are (similar to case hardened steels, which should not be discussed here) prepared by heating metals and alloys in nitrogen or ammonia, occasionally diluted with an inert gas. Mainly titanium and... 

Both early transition metal nitrides and carbides were prepared with MAFBS. Nitrides were prepared exclusively from reactions between metal powders and fluidizing Nj gas. Carbides were prepared either through fluidization of metal and carbon black powders with Ar gas or from reaction between metal powders and... 

Transition-metal nitrides where nitrogen is present as an interstitial are prepared by the reaction of the metals with NH3 around 1470 K. BN is obtained by heating boron with NH3 at white heat. Metal nitrides are also prepared by the reaction of metal chlorides with NHj. For example, MN and WN films are prepared by the reaction of NH3 with AICI3 and WCl respectively. Recently, nitrides of Ti, Zr, Hf and lanthanides have been prepared by the reaction of lithium nitride with the anhydrous metal chlorides [8] ... 

Kumta and co-workers [20] have used a three-step sol-gel-based procedure to prepare ternary transition metal nitrides involving heat treatment under ammonia of a metal organic hydroxide precursor. This route consists in the hydrolysis of a polymeric liquid precursor to form a metal-organic hydroxide. Thermochemical decomposition of the metal-organic hydroxide precursor under ammonia leads to ternary nitrides such as NijMOjN, FeWN and Ti AIN. DiSalvo and co-workers incorporated alkaU metal ions to increase the stability of the nitrides compared to binary compounds. They used a sol-gel-based route to prepare ternary alkali and alkaline-earth metal nitrides such as NaTaN, KTaN and NaNbN [21, 22]. 

A patent has been issued for the preparation of pure ThN or its mixture with either U, Pu, or any other of a number of the high-melting transition metal nitrides [31]. To prepare pure ThN, an intimate fine powder mixture of C with Th oxalate in the mole ratio of 1 to 2 is heated in streaming H2 or Ar + H2 to above 600X (the oxalate decomposes at 750 to 800°C) after which the product is evacuated and the carbothermal reduction completed at 1100 to 1300°C. The product is converted to the nitride in streaming N2 by heating to 1750 to 1800°C until evolution of CO is complete. 

Pipes et al. [72] reported the preparation and structure of an unusual transition metal nitride. How many electrons are associated with the metal What would be the level ordering and electron occupation for the Os d orbitals in this molecule ... 

M Yoshida, M Nishioka, S Somiya. Rapid preparation of titanium and other transition-metal nitride and carbide powders by a carbo-reduction method using arc-image heating. In Ref. 8, p 406. 

A variety of routes is available for the preparation of metal-thionitrosyl complexes. The most common of these are (a) reaction of nitride complexes with a sulfur source, e.g., elemental sulfur, propylene sulfide or sulfur halides, (b) reaction of (NSC1)3 with transition-metal complexes, and (c) reaction of [SN]" salts with transition-metal complexes. An example of each of these approaches is given in Eq. 7.1,... 

Several patents dealing with the use of volatile metal amidinate complexes in MOCVD or ALD processes have appeared in the literature.The use of volatile amidinato complexes of Al, Ga, and In in the chemical vapor deposition of the respective nitrides has been reported. For example, [PhC(NPh)2]2GaMe was prepared in 68% yield from GaMes and N,N -diphenylbenzamidine in toluene. Various samples of this and related complexes could be heated to 600 °C in N2 to give GaN. A series of homoleptic metal amidinates of the general type [MIRCfNROilnl (R = Me, Bu R = Pr, BuO has been prepared for the transition metals Ti, V, Mn, Fe, Co, Ni, Cu, Ag, and La. The types of products are summarized in Scheme 226. The new compounds were found to have properties well-suited for use as precursors for atomic layer deposition (ALD) of thin films. 

As nitridoborates are known as A3(BN2) for alkaline elements (A = Li, Na) and as AE3(BN2)2 for alkaline-earth elements (AE = Ca, Sr, Ba) it would be interesting to find methods for the synthesis of nitridoborates of transition or lanthanide elements. Can they be made straightforward Hke Ii3(BN2) and AE3(BN2)2 from metal nitrides and layer-like a-BN, or do they require new preparative strategies - if they can be made at all ... 

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