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Electrochemical determination of thermodynamic properties of MnF2 and CoF2.
Albany, OR: U.S. Department of the Interior, Bureau of Mines, RI 8973, 1985 Jan; :1-8
The Bureau of Mines investigated the standard Gibbs energies of formation, AGF deg., for MnF2 (manganese difluoride) and CoF2 (cobalt difluoride). High-temperature galvanic cells employing CaF2 (calcium difluoride) as the solid electrolyte were used to measure the open-circuit potentials for the cell reactions Mn(c) + NiF2(c) = MnF2(c) + Ni(c) and Co(c) + NiF2(c) = CoF2(c) + Ni(c). Combination of the standard Gibbs energy changes for these reactions with the standard Gibbs energy of formation of NiF2 yielded the following: AGF deg. (MnF2) = (-203,008 + 30.96T)+/-560(745.7-1,078.3 K) and AGF deg. (CoF2) = (-159,090 + 32.13T)+/-420 (769.5-1,026.8 K), where AGF deg. is expressed in calories per mol (1 cal = 4.184J) and T is expressed in kelvins. The standard enthalpies of formation deltaHF deg., Derived by the third-law method, are deltaHF deg. 298(Mnf2) = -204, 633+/-560 cal/mol and deltaHF deg. 298(Cof2) = -161,166+/-420 cal/mol.
IH; Report of Investigations
Albany, OR: U.S. Department of the Interior, Bureau of Mines, RI 8973
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