Calomel

Formula : Hg2Cl2

Family: 
Chlorides
Space group: 
Tetragonal - Ditetragonal Dipyramidal H-M Symbol (4/m 2/m 2/m) Space Group: I 4/mmm
Dana class: 
9.1.8.1 (9) Anhydrous and Hydrated Halides (9.1) where A X (9.1.8) Dana Group
High temperature: 
Stable at room temperature
Geological context: 
Oxidized mercury deposits, supergene environment

Dernière mise à jour le 25.01.2021

THERMODYNAMICS

Individual properties (298.15 K)
M
g·mol-1
 V°
cm3·mol-1
 ΔGºf
J·mol-1
 ΔHºf
J·mol-1
 Sº
J·mol-1·k-1
 CP
J·mol-1·K-1
472.085 32.940 (Ref.: 95rob/hem) Robie R.A., and Hemingway B.S., 1995. Thermodynamic properties of minerals and related substances at 298.15 K and 1 Bar (105 Pascals) pressure and at higher temperatures. U.S. Geol. Survey Bull., 2131, 461 pp. -210725 (Ref.: Internal calculation) -265370 (Ref.: 89cox/wag) Cox J.D., Wagman D.D., and Medvedev V.A., 1989. CODATA Key Values for Thermodynamics. Hemisphere Publishing Corp., New York, 279 p. 191.600 (Ref.: 89cox/wag) Cox J.D., Wagman D.D., and Medvedev V.A., 1989. CODATA Key Values for Thermodynamics. Hemisphere Publishing Corp., New York, 279 p. 101.97 (Ref.: 85cha/dav) Chase, M. W., Jr., C. A. Davies, J. R. Downey, Jr., D. J. Frurip, R. A. McDonald, and A. N. Syverud 1985. JANAF Thermochemical Tables, 3rd. ed., J. Phys. Chem. Ref. Data 14, Suppl. 1, Am. Chem. Soc. and Am. Inst. of Physics, Washington, D. C.
CP(T) = a + b·T + ·c·T-2 (T in Kelvin)
a
J·mol-1·K-1
 b * 103
J·mol-1·K-2
 c * 10-5
J·K·mol-1
 Maier Kelley Ref.
97.19 26.28 -2.71 (Ref.: 85cha/dav) Chase, M. W., Jr., C. A. Davies, J. R. Downey, Jr., D. J. Frurip, R. A. McDonald, and A. N. Syverud 1985. JANAF Thermochemical Tables, 3rd. ed., J. Phys. Chem. Ref. Data 14, Suppl. 1, Am. Chem. Soc. and Am. Inst. of Physics, Washington, D. C.
Reaction properties

Calomel ⇌ 2Cl- + Hg2+2

298.15 K, 1 bar log10K: -17.84 ΔH°r:98080 J·mol-1 (Ref.: 89cox/wag) Cox J.D., Wagman D.D., and Medvedev V.A., 1989. CODATA Key Values for Thermodynamics. Hemisphere Publishing Corp., New York, 279 p.
T(°C) 0 25 60 100 150 200 250 300
log10K -19.48 -17.84 -16.12 -14.72 -13.56 -12.92 -12.74 -13.09
log10K(T) = A + B·T + C·T-1 + D·log10(T) + E·T−2 (T in Kelvin)
A B C D E
-1475.230473 -0.240166 75071.958933 537.756500 -4750813.723496