Macroscopic rates, microscopic observations, and molecular models of the dissolution of carbonate phases.

Duckworth, Owen W. (Harvard University, Cambridge, MA) ; Cygan, Randall Timothy ; Martin, Scot T. (Harvard University, Cambridge, MA)

Sandia National Laboratories

关键词: Carbonate Minerals.;    Models, Molecular.;    37 Inorganic, Organic, Physical And Analytical Chemistry;    Microchemistry.;    Molecular Models;   

DOI  :  10.2172/919119
RP-ID  :  SAND2004-1838
RP-ID  :  AC04-94AL85000
RP-ID  :  919119

美国|英语

来源: UNT Digital Library

【 摘 要 】

Bulk and surface energies are calculated for endmembers of the isostructural rhombohedral carbonate mineral family, including Ca, Cd, Co, Fe, Mg, Mn, Ni, and Zn compositions. The calculations for the bulk agree with the densities, bond distances, bond angles, and lattice enthalpies reported in the literature. The calculated energies also correlate with measured dissolution rates: the lattice energies show a log-linear relationship to the macroscopic dissolution rates at circumneutral pH. Moreover, the energies of ion pairs translated along surface steps are calculated and found to predict experimentally observed microscopic step retreat velocities. Finally, pit formation excess energies decrease with increasing pit size, which is consistent with the nonlinear dissolution kinetics hypothesized for the initial stages of pit formation.