The vapor pressures in equilibrium over CuF2, AgF2, and AgF were measured by the torsion-effusion method. CuF2 and AgF vaporized congruently. The temperature dependences of the vapor pressure of these compounds were found to fit the following equations: CuF2(s), log(p/kPa) ) (9.78 ( 0.10) - (12690 ( 100)(T/K) (from (881 to 1051) K) and AgF(l), log(p/kPa) ) (7.83 ( 0.20) - (10700 ( 300)(T/K) (from (880 to 1074) K). Treating the vapor pressure data by the second- and third-law methods, the standard sublimation enthalpies of these compounds, AsubHdeg (298 K) ) (260 ( 4) kJ * mol-1 and (240 ( 10) kJ * mol-1 for CuF2 and AgF, respectively, were calculated. In the covered temperature range (from (655 to 776) K), AgF2 decomposes into fluorine and solid or molten AgF so that two temperature dependences of the fluorine pressure above this compound in equilibrium with AgF(s) and AgF(l), log(p/kPa) ) (11.39 ( 0.30) - (11060 ( 300)(T/K) (from (655 to 706) K) and log(p/kPa) ) (10.27 ( 0.20) - (10220 ( 200)(T/K) (from (710 to 776) K), respectively, were determined. At these temperatures, fluorine is partially decomposed so that two partial molar standard enthalpies of AgF2 associated to the sublimation reactions, AgF2(s) f AgF(s) + F(g) and AgF2(s) f AgF(s) + 1/2F2(g), AsubHdeg (298 K) ) (195 ( 10) kJ * mol-1 and (125 ( 5) kJ * mol-1, were calculated.
Compounds
#
Formula
Name
1
CuF2
copper difluoride
2
AgF
silver fluoride
Datasets
The table above is generated from the ThermoML associated json file (link above).
POMD and RXND refer to PureOrMixture and Reaction Datasets. The compound numbers are included in properties, variables, and phases, if specificied;
the numbers refer to the table of compounds on the left.