Carbide, iron complex

Carbide, iron complex, 26 246 Carbido carbonyl ruthenium clusters. 

C, Carbide, iron complex, 26 246 ruthenium cluster complexes, 26 281-284 CHFiO, Acetic acid, trifluoro-, tungsten complex, 26 222... 

C, Carbide, iron complex, 26 246 ruthenium cluster complexes, 26381-284 CHF3O3S, Methanesulfonic add, trifluoro-, iridium, manganese, and rhenium com-iriexes, 26 114,115,120 platinum complex, 26 126 CHOS2, Dithioaubonic add, 27 287 CH2> Methylene, osmium complex, 27 206 CH2O2, Formic add, rhenium complex, 26 112... 

Irons of the compositions indicated above all have structures similar to that shown in Fig. 3.52, that is, a uniform dispersion of chromium-iron complex carbides in a matrix of chromium-containing ferrite. The chromium content of the ferrite is not known, although it is assumed to be about 10-13%. The... 

Complex Carbides. Complex carbides are ternary or quaternary intermetaUic phases containing carbon and two or more metals. One metal can be a refractory transition metal the second may be a metal from the iron or A-groups. Nonmetals can also be incorporated. 

FejC (also called "iron carbide" or "cementite") Complex A hard and brittle chemical compound of Fe and C containing 25 atomic % (6.7 wt%) C. 

The high-chromium irons undoubtedly owe their corrosion-resistant properties to the development on the surface of the alloys of an impervious and highly tenacious film, probably consisting of a complex mixture of chromium and iron oxides. Since the chromium oxide will be derived from the chromium present in the matrix and not from that combined with the carbide, it follows that a stainless iron will be produced only when an adequate excess (probably not less than 12% of chromium over the amount required to form carbides is present. It is commonly held, and with some theoretical backing, that carbon combines with ten times its own weight of chromium to produce carbides. It has been said that an increase in the silicon content increases the corrosion resistance of the iron this result is probably achieved because the silicon refines the carbides and so aids the development of a more continuous oxide film over the metal surface. It seems likely that the addition of molybdenum has a similar effect, although it is possible that the molybdenum displaces some chromium from combination with the carbon and therefore increases the chromium content of the ferrite. 

An XPS Investigation of iron Fischer-Tropsch catalysts before and after exposure to realistic reaction conditions is reported. The iron catalyst used in the study was a moderate surface area (15M /g) iron powder with and without 0.6 wt.% K2CO3. Upon reduction, surface oxide on the fresh catalyst is converted to metallic iron and the K2CO3 promoter decomposes into a potassium-oxygen surface complex. Under reaction conditions, the iron catalyst is converted to iron carbide and surface carbon deposition occurs. The nature of this carbon deposit is highly dependent on reaction conditions and the presence of surface alkali. 

Graphite materials produced at 600-1100°C may find applications in lithium batteries and supercapacitors. Currently, similar flakes are produced in a complex process including graphitization at above 2500°C,16 followed by intercalation and exfoliation of graphite15. Here we demonstrate that synthesis of graphite from iron carbide can be done in one step at moderate temperatures. 

For the development of a selectivity model it is helpful to have a picture of the surface of the catalyst to ht the explanation of how the product spectrum is formed. The fundamental question regarding the nature of the active phase for the FT and water-gas shift (WGS) reactions is still a controversial and complex topic that has not been resolved.8 Two very popular models to describe the correlations between carbide phase and activity are the carbide9 and competition models.10 There are also proposals that magnetite and metallic iron are both active for the FT reaction and carbides are not active11. These proposals will not be discussed in detail and are only mentioned to highlight the uncertainty that is still present on the exact phase or active site responsible for the FT and WGS reactions. 

Iron(II) formate dihydrate, 14 537 Iron(II) fumarate, 14 537 Iron gelbs, 19 399, 400 Irondl) gluconate dihydrate, 14 541 Iron group carbides, 4 690-692 Iron halides, 14 537-540 Iron hydroxide, water exchange rates and activation parameters of hexaaqua complexes, 7 589t Iron(II) hydroxide, 14 542 Iron(III) hydroxide, 14 542 Iron hydroxides, 14 541—542 Iron(II) iodide, 14 540 Iron(III) iodide, 14 540 Iron/iron alloy plating, 9 813—814. See also Fe entries... 

The smallest member of the iron carbide family is neither a carbonyl nor a cluster, but is included here since its structure is an example of the lowest coordination number for a carbon atom in a transition metal complex. The... 

D. Mansuy, J.-P. Lecomte, J.-C. Chottard, and J.-F. Bartoli, Formation of a Complex with a Carbide Bridge Between Two Iron Atoms from the Reaction of (Tetraphenyl-porphyrin)iron(II) with Carbon Tetraiodide, Inorg. Chem. 20, 3119-3121 (1981). 

Iron and Carbon-Iron Carbides—Cementite—Iron Carbonyls—Ferrous Carbonate-Complex Iron Carbonates—Thiocarbonates. 

---