Flux synthesis

Molecular dynamics, 283,285,296, 298 Molten-salt flux synthesis, 392 Monoclinic, 111 Mono-metallofullerenes, 124 Mosander, Carl Gustaf, 6 Mosandrum, 7 Moseley, Henry, 54 Moseley s law, 4... 

In a typical flux synthesis, a significant excess of one or more constituents is added to the reaction charge, which is loaded in an appropriate (inert) crucible and sealed under inert atmosphere either in a fused silica ampoule or welded container, depending on the composition. A plug of quartz wool is often placed above the reaction charge, either inside the crucible or directly above it, to act as a filter to separate the flux, post-crystal growth [113]. After an adequate soak at elevated... 

It is possible to prepare very heavy elements in thermonuclear explosions, owing to the very intense, although brief (order of a microsecond), neutron flux furnished by the explosion (3,13). Einsteinium and fermium were first produced in this way they were discovered in the fallout materials from the first thermonuclear explosion (the "Mike" shot) staged in the Pacific in November 1952. It is possible that elements having atomic numbers greater than 100 would have been found had the debris been examined very soon after the explosion. The preparative process involved is multiple neutron capture in the uranium in the device, which is followed by a sequence of beta decays. Eor example, the synthesis of EM in the Mike explosion was via the production of from followed by a long chain of short-Hved beta decays,... 

CoF is used for the replacement of hydrogen with fluorine in halocarbons (5) for fluorination of xylylalkanes, used in vapor-phase soldering fluxes (6) formation of dibutyl decalins (7) fluorination of alkynes (8) synthesis of unsaturated or partially fluorinated compounds (9—11) and conversion of aromatic compounds to perfluorocycHc compounds (see Fluorine compounds, organic). CoF rarely causes polymerization of hydrocarbons. CoF is also used for the conversion of metal oxides to higher valency metal fluorides, eg, in the assay of uranium ore (12). It is also used in the manufacture of nitrogen fluoride, NF, from ammonia (13). 

The GdAlgB O QiCe ", Tb " is synthesized by a soHd-state firing of the rare-earth coprecipitated oxide plus boric acid and MgCO at 900° C in a slightly reducing atmosphere. As in the case of the lanthanum phosphate phosphor, a flux is usually used. The synthesis of this phosphor is further comphcated, however, by the fact that it is a ternary system and secondary phases such as gadolinium borate form and must then react to give the final phosphor. 

Potassium cyanide [151 -50-8] KCN, a white crystalline, deUquescent soHd, was initially used as a flux, andlater for electroplating, which is the single greatest use in the 1990s. The demand for potassium cyanide was met by the ferrocyanide process until the latter part of the nineteenth century, when the extraordinary demands of the gold mining industry for alkah cyanide resulted in the development of direct synthesis processes. When cheaper sodium cyanide became available, potassium cyanide was displaced in many uses. With the decline in the use of alkah cyanides for plating the demand for potassium cyanide continues to decline. The total world production in 1990 was estimated at about 4500 t, down from 7300 t in 1976. 

Steam reforming is an important proeess to generate hydrogen for sueh uses as ammonia synthesis beeause of the high endothermie heat reaetion and its rapidity. High heat fluxes with a direet-fired furnaee are required. Although many steps of reaetions are possible, the typieal reaetion steps are as follows ... 

In order to develop a rational approach to improving rates of metabolite production, it is necessary to consider the fate of the nutrients that are required for its synthesis. However, overcoming the major flux control points within a metabolic pathway may not lead to metabolite overproduction if the energetic consequences of the alteration are unfavourable to the organism. 

It is obvious that rapid metabolite production requires high fluxes of carbon through the metabolic systems responsible for its synthesis. The rate of metabolite production, for a wide range of micro-organisms, has been shown to increase with decrease in... 

Kanatzidis MG, Pottgen R, Jeitschko W (2005) The metal flux a preparative tool for the exploration of intermetallic compounds. Angew Chem Int Ed 44 6996-7023 Trindade T, O Brien P, Pickett NL (2001) Nanocrystalline semiconductors Synthesis, properties, and perspectives. Chem Mater 13 3843-3858... 

Low-temperature solvents are not readily available for many refractory compounds and semiconductors of interest. Molten salt electrolysis is utilized in many instances, as for the synthesis and deposition of elemental materials such as Al, Si, and also a wide variety of binary and ternary compounds such as borides, carbides, silicides, phosphides, arsenides, and sulfides, and the semiconductors SiC, GaAs, and GaP and InP [16], A few available reports regarding the metal chalcogenides examined in this chapter will be addressed in the respective sections. Let us note here that halide fluxes provide a good reaction medium for the crystal growth of refractory compounds. A wide spectrum of alkali and alkaline earth halides provides... 

---