Manganese thermodynamic properties

E. A. Brandes and R. E. Flint, Manganese Phase Diagrams, The Manganese Centre, Paris, 1980 L. B. Pankratz, Thermodynamic Properties of Elements and Oxides, Bull. 672, U.S. Bureau of Mines, Washington, D.C., 1982. 

NO reduction by CO, 28 162 olefin oxidation, 27 241,242 water-gas shift, 28 118,119 coordination number, 30 265 -copper alloy, 26 75 -copper alloy films thermodynamic properties of, 22 118 -copper oxide, 27 90,91 -manganese oxide, 27 91,92... 

Adequacy of Thermodynamic Data. Data on several important aluminosilicates appear to be insufficient for a detailed discussion of all equilibria. Information on the influence of solid solutions or coprecipitated phases on thermodynamic properties appears to be rather limited, as is that for metastable non-stoichiometric oxides (e.g., of manganese) and surface complexes. 

The relative positions of the H20—02 boundary and the Mn2+—Mn02 boundaries for both 10"3 and 10"7M activities of aqueous Mn2+ indicate that for pH values greater than about 4, Reaction 58 is spontaneous. Similarly, the pure solid phases MnCOa and Mn(OH)2 are unstable with respect to oxidation to MnO >. Extensive interpretations of manganese chemistry in terms of the thermodynamic properties of the oxides and on other solid phases and solution species of manganese can be found in the recent literature (3,14, 24). 

V.N. Yeremenko, G.M. Lukashenko, V.R. Sidorko. Thermodynamic properties of vanadium, chromium and manganese silicides at elevated temperatures // Rev.Intern. Haut.Temp.Refract.- 1975.- V.12, No.3.- P.237-240. 

Manganese—No very reliable vapour pressure data on manganese appear to be available. Kelley et have measured the thermodynamic properties of manganese, and combine them with such vapour pressure data as are available to give the heat of vaporization. The N.B.S.529 on this basis adopt... 

Fritsch S, Navrotsky A (1996) Thermodynamic properties of manganese oxides. J Am Ceram Soc 79 1761-1768... 

THERMODYNAMIC PROPERTIES OF MANGANESE GERMANIDES Literature Cited... 

The coordination chemistry [8] and electrochemical properties [9-11] of manganese-containing compounds have been reviewed on a number of occasions. These collections contain primarily thermodynamic and (to a lesser extent) kinetic information on compounds of relatively simple composition. The objective in this chapter is to provide a descriptive summary of the electrochemical properties of a wide range of manganese compounds. There is generous coverage of coordination complexes, which seeks to illustrate relationships between structure and... 

This volume of the Handbook illustrates the rich variety of topics covered by rare earth science. Three chapters are devoted to the description of solid state compounds skutteru-dites (Chapter 211), rare earth-antimony systems (Chapter 212), and rare earth-manganese perovskites (Chapter 214). Two other reviews deal with solid state properties one contribution includes information on existing thermodynamic data of lanthanide trihalides (Chapter 213) while the other one describes optical properties of rare earth compounds under pressure (Chapter 217). Finally, two chapters focus on solution chemistry. The state of the art in unraveling solution structure of lanthanide-containing coordination compounds by paramagnetic nuclear magnetic resonance is outlined in Chapter 215. The potential of time-resolved, laser-induced emission spectroscopy for the analysis of lanthanide and actinide solutions is presented and critically discussed in Chapter 216. 

Crystal field theory is one of several chemical bonding models and one that is applicable solely to the transition metal and lanthanide elements. The theory, which utilizes thermodynamic data obtained from absorption bands in the visible and near-infrared regions of the electromagnetic spectrum, has met with widespread applications and successful interpretations of diverse physical and chemical properties of elements of the first transition series. These elements comprise scandium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel and copper. The position of the first transition series in the periodic table is shown in fig. 1.1. Transition elements constitute almost forty weight per cent, or eighteen atom per cent, of the Earth (Appendix 1) and occur in most minerals in the Crust, Mantle and Core. As a result, there are many aspects of transition metal geochemistry that are amenable to interpretation by crystal field theory. 

An extensive survey of the thermodynamic and kinetic properties of manganese in natural aqueous systems has been presented by Morgan (3). From a thermodynamic standpoint, Mn(II) is unstable with respect to oxidation in natural waters. The kinetics of the oxidation reactions are sufficiently slow so that Mn(II) can exist as a metastable species in natural waters. The solubility of Mn(II) in most natural systems probably is limited by the solubility of MnC03. Soluble complexes such as MnHCCV make varying contributions to the total soluble Mn(II) species in natural waters. Some of the equilibria which are relevant to this study are listed in Table I. 

A method for the generation of variable and accurately determined partial pressures of sulphur has been described. The technique enables the study of the thermodynamic and electrical properties of metal-sulphur systems at high temperatures to be carried out and has application to studies of phase diagrams, non-stoicheiometry, electrical conductivity, and of the Seebeck effect. The precision of the stability of the sulphur pressures obtained is controlled by direct determination at high temperatures, using a manganese sulphide probe. 

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