Abstract
The chemical potential of oxygen defined by the equilibrium:
has been measured between 850 and 1250 K via an electrochemical method using calcia-stabilized zirconia electrolytes and either Ni+NiO or Cu+Cu2O as the reference electrode. The results are:
where μO2 is in J·mol-1,T in kelvins, and the reference pressure for O2 is 1 bar (105 Pa). (Values in terms of log-\(f_{O_2 }\)may be obtained from the above expression by dividing by RTln10, whereR=8.31441 J.K-1·mol-1). The standard enthalpy of formation of ReO2 is-444.350±0.400 (1σ) kJ·mol-1, requiring a significant modification to previously published estimates. These results were checked in hydrothermal experiments using the double capsule method with NiO+Ni−Pd alloy as an oxygen sensor. Reversals atP=1 kbar over theT range 823 to 1073 K are in good agreement with the electrochemical measurements. These latter results also serve to demonstrate: (1) the usefulness of the “redox sensor” method; (2) the viability of using Re+ReO2 as a buffer in hydrothermal experiments. Re+ReO2 lies nearly midway between the Ni+NiO and Fe3O4+Fe2O3 buffers in μO2-T space, and thus fills a petrologically important gap in the range of μO2s which can be covered by accurately calibrated oxygen buffers.
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Battles JE, Gunderson GE, Edwards RK (1968) A mass spectrometric study of the rhenium-oxygen system. J Phys Chem 72:3963–3969
Carmichael ISE (1991) The redox state of basic and silicic magmas: a reflection of their source regions? Contrib Mineral Petrol 106:129–141
Chou I-Ming (1987) Oxygen buffer and hydrogen sensor techniques at elevated pressures and temperatures. In: Ulmer GC, Barnes HC Jr (eds) Hydrothermal experimental techniques. Wiley, New York, pp 60–99
Eugster HP (1957) Heterogeneous reactions involving oxidation and reduction at high pressures and temperatures. J Chem Phys 26:1760–1761
Eugster HP, Wones DR (1962) Stability relations of the ferruginous biotite, annite. J Petrol 3:82–125
Franco JI, Kleykamp H (1971) Thermodynamics of the system Rhenium-Oxygen (in german). Ber Bunsenges Phys Chem 75:934–938
Hemingway BS (1990) Thermodynamic properties for bunsenite, NiO, magnetite, Fe3O4, and haematite, Fe2O3, with comments on selected oxygen buffer reactions. Am Mineral 75:781–790
Huebner JS (1971) Buffering techniques for hydrostatic systems at elevated pressures. In: Ulmer GC (ed) Research techniques for high pressure and high temperature. Springer-Verlag, Berlin Heidelberg New York, pp 123–178
Hultgren R, Desai PD, Hawkins DT, Gleiser M, Kelley KK, Wagman DD (1973) Selected values of the thermodynamic properties of the elements. Am Soc Met
Kerrick DM (1987) Cold-seal systems. In: Ulmer GC, Barnes HC Jr (eds) Hydrothermal experimental techniques, Wiley, New York, pp 293–323
King EG, Richardson DW, Mrazek RV (1969) Heats of formation of three oxides of rhenium. US Bur Mines Rep Invest 7323
Magnéli A (1957) Studies on rhenium oxides. Acta Chem Scand 11:28–33
Massalski TB (1986) Binary alloy phase diagrams, vols 1–2. Am Soc Met
O'Neill HStC (1988) Systems Fe−O and Cu−O: thermodynamic data for the equilibria Fe−“FeO,” Fe−Fe3O4, “FeO”−Fe3O4, Cu−Cu2O, and Cu2O−CuO from EMF measurements. Am Mineral 73:470–486
O'Neill HStC, Pownceby MI (1993a) Thermodynamic data from redox reactions at high temperatures: zirconia electrolytes, with revised values for the Fe−“FeO”, Co−CoO, Ni−NiO and Cu−Cu2O oxygen buffers, and new data for the W-WO2 buffer. Contrib Mineral Petrol 114:296–314
O'Neill HStC, Pownceby MI (1993b) Thermodynamic data from redox reactions at high temperatures. II. The MnO−Mn3O4 oxygen buffer, and implications for the thermodynamic properties of MnO and Mn3O4. Contrib Mineral Petrol 114:315–320
Pankratz LB (1982) Thermodynamic properties of elements and oxides. US Bur Mines Bull 672
Pownceby MI, O'Neill HStC (1994) Thermodynamic data from redox reactions at high temperatures. III. Activity-composition relations in Ni−Pd alloys from EMF measurements at 850–1250 K, and calibration of the NiO+Ni−Pd assemblage as a redox sensor. Contrib Mineral Petrol 116:327–339
Ramanarayan TA (1980) Limiting factors in measurements using solid electrolytes. In: Subbarao EC (ed) Solid electrolytes and their applications. Plenum Press, New York, pp 81–98
Rudert V, Chou I-M, Eugster HP (1976) Temperature gradients in rapid-quench cold-seal pressure vessels. Am Mineral 61:1012–1015
Stuve JM, Ferrante MJ (1976) Thermodynamic properties of rhenium oxides, 8 to 1400 K. US Bur Mines Rep Invest 8199
Taylor JR, Wall VJ, Pownceby MI (1992) The calibration and application of accurate redox sensors. Am Mineral 77:284–295
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Pownceby, M.I., O'Neill, H.S.C. Thermodynamic data from redox reactions at high temperatures. IV. Calibration of the Re-ReO2 oxygen buffer from EMF and NiO+Ni-Pd redox sensor measurements. Contr. Mineral. and Petrol. 118, 130–137 (1994). https://doi.org/10.1007/BF01052864
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DOI: https://doi.org/10.1007/BF01052864