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USGS · 70161889

The enthalpies of formation of nesquehonite, MgCO3 * 3H2O, and hydromagnesite, 5MgO * 4CO2 * 5H2O

Bruce S. Hemingway·Richard A. Robie
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Abstract

The enthalpies of formation, ΔH° f , of nesquehonite, MgCO 3 * 3H 2 O, and hydromagnesite, 5MgO * 4CO 2 * 5H 2 O, have been determined by HCl solution calorimetry. For the reaction MgO(c) + CO 2 (g) + 3H 2 O(l) = MgCO 2 * 3H 2 O(c), the enthalpy change at 298.15 K is -29,781*40 cal mor' . For the reaction 5MgO(c) + 4CO 2 + 5H 2 O = 5MgO * 4CO 2 * 5H 2 O, the enthalpy change at 298.15 K is -120,310±120 cal. For MgCO 3 * 3H 2 O the standard molar enthalpy and standard Gibbs free energy of formation, ΔH° f,298 and ΔG° f,298 are -472,576+110 and 412,040±120 cal. ΔH° f,298 and ΔG° f,298 for 5MgO * 4CO 2 * 5H 2 O are -1,557,090±250 and -1,401,71 0±250 cal.

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Bruce S. Hemingway, Richard A. Robie. 1973. The enthalpies of formation of nesquehonite, MgCO3 * 3H2O, and hydromagnesite, 5MgO * 4CO2 * 5H2O. https://pubs.usgs.gov/publication/70161889

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