Calcite lattice

Trace elements can be adsorbed on the surface of calcite, influencing their solubility in calcareous soils of arid and semi-arid zones. The carbonate bound fraction is the major solid-phase component for many trace elements (Cd, Pb, Zn, Ni and Cu) in arid and semi-arid soils, especially in newly contaminated soils (Table 5.3). In Israeli arid soils treated with metal nitrates, the carbonate bound fraction is the largest solid-phase component (60-80%, 50-60%, 40-60%, 30-40%, and 25-36% for Cd, Pb, Zn, Ni, and Cu respectively). Divalent metallic cations at low aqueous concentrations first associate with calcite via adsorption reactions. Then they may be incorporated into the calcite lattice as a co-precipitate by recrystallization (Franklin and Morse, 1983 Komicker et al., 1985 Davis et al., 1987 Zachara et al., 1988 Reeder and Prosky, 1986 Pingitore and... 

These EPR studies provide Independent evidence for at least the partial Incorporation of Sr2+ In calcite lattice sites and the exclusion of Ba2+ from lattice sites. 

Di Benedetto, F., Costagliola, P., Benvenuti, M. et al. (2006) Arsenic incorporation in natural calcite lattice evidence from electron spin echo spectroscopy. Earth and Planetary Science Letters, 246(3-4), 458-65. 

Ishikawa and Ichikuni (1984) also conducted a study of the coprecipitation of sodium with calcite. They suggested that Na+ is located at interstitial sites in the calcite lattice, and good agreement was observed between their predicted Na concentrations and those in natural calcites for waters up to about a salinity of 10. At higher salinities the natural samples generally had higher Na concentrations than... 

Chave (1952) reported a linear relationship between the position of the 1014 diffraction peak of skeletal calcites and their Mg concentrations, as determined by wet chemical techniques, over the range 0-18 mole % MgC03. At higher Mg concentrations, the relationship was observed to be nonlinear. He concluded "that Mg was replacing Ca in the calcite lattice, shrinking it, and forming a solid solution between calcite and dolomite" (Chave, 1981). 

Applying the same principle as that used above, we can classify the normal vibrations of the CO3 ion in the calcite lattice by using the correlation method. As discussed in... 

Figure 22. (A) The specular reflectivity of the calcite-water interface (squares), with similar data for a calcite surface in contact with a 5 mM solution of stearic acid in methanol (The calcite-water data are offset vertically by a factor of 10, for clarity). The measurements were performed in a transmission cell. The solid lines are best-fit structure factor calculations for selected models. The thick solid line through the stearate data is optimized for an extended stearate molecule adsoibed on top of the calcite surface, as shown in (B). The thin solid line through the stearate data is optimized for the carboxylic head group substituting for surface carbonate ions of the calcite lattice. (B) Best-fit model for the stearate monolayer adsorbed on calcite.

The calcite lattice will have trigonal symmetry with the main axis in the direction of the ternary axis of the cube, after the deformation has happened. 

FIGURE 4.54 Left the calcite lattice after U.S. Naval Research Laboratory/Center for Computational Materials Science (2003). Right the structural cell of CaCOj with specifyii of its Pearson spatial notation, along the International notation, and also by the number of the spatial group, according to the Tables 2.17 and 2.16, respectively after Penkala (1974). 

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