Chemical transport, preparation

Generally, it is not important in which form the components are introduced into the transport tube, because the transport reaction transfers the whole system into a reversible state. In the preparation of NbS2Cl2, for example, Nb and S2C12, as well as Nb, S, and NbCls, have been used as starting materials (339). The principles of chemical transport reactions are treated in refs. 241, 336, 337, 338). 

The nitrides can be prepared by heating a metal powder in an N2 or NH3 atmosphere to temperatures above 1100°C. The carbides form upon heating mixtures of the metal powders with carbon to temperatures of about 2200 °C. Both the nitrides and carbides can also be made by chemical transport reactions by the van Arkel-de Boer method if the metal deposition takes place in an atmosphere of N2 or a hydrocarbon. Their remarkable properties are ... 

The tellurate EIg2Te207 is dimorphic. Both forms have been prepared from HgO, Te02, and Te03 by chemical transport reactions with HgCl2 as transport agent.136 In both modifications [Te(VI)Oe] octahedra are connected to infinite... 

Single-crystal preparation by means of chemical transport reactions. (Ni-Sn-S compounds as an example)... 

Single crystals of metal rich sulphides (Ni6SnS2, Ni9Sn2S2) have been prepared by chemical transport reactions (Baranov et al. 2003). The stoichiometric mixtures of the elements were previously annealed in evacuated silica ampoules at 540°C for... 

There are several comprehensive textbooks and review articles devoted to organic superconductors [3,4,182-186] which describe design and preparation, crystal and band structures, chemical, transport, magnetic, optical, and thermal properties, and theory. 

Chemical transport of solids is a well known preparative technique. As was pointed out by Schafer41, information on thermodynamic properties of heterogeneous systems can also be obtained from experiments involving chemical transport. In particular, the dependence of chemical equilibrium of a heterogeneous reaction of the type... 

Single crystals of CuInS2 and the layered semiconductors were prepared by chemical transport reactions. Iodine transported n-type material had the best electronic properties among the CVT grown samples and was used here. 

Cu-exchanged zeolite catalyst containing strong water tolerance and hydrothermal stability, although a method for preparation by using a solid ion exchange chemical transport technique has been suggested. 

Chemical-transport reactions have been used to prepare single crystals of triiron tetraoxide (magnetite) and other ferrites, which comprise the majority of all known ferrimagnetic mate-... 

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