Minerals, bonding interactions

Schulten, H.-R. (2002). New approaches to the molecular structure and properties of soil organic matter Humic-, xenobiotic-, biological-, and mineral-bonds. In Soil Mineral-Organic Matter-Microorganism Interactions and Ecosystem Health. Developments in Soil Science,Vol. 28A, Violante, A., Huang, P. M., Bollag, J.-M., and Gianfreda, L., eds., Elsevier B. V., Amsterdam, pp. 351-381. 

Figure 11.8 Details of the spin-down (P-spin) orbital energy levels at q = 0 showing the different types of Fe(34)-Fe(34) bonding interactions (from Sherman, 1987a). The only occupied orbital is the 16a level. Excitation of the p-spin electron between the 16a, and 17a levels corresponds to a Fe2+ —>Fe3 IVCT transition observed in optical spectra of minerals (cf. table 4.2).

HYDROGEN-BONDED INTERACTIONS IN SOIL MINERALS AND THEIR SURFACES... 

The bonding characteristics determine the properties of the minerophilic and hydrophilic groups. The selectivity of the mineral-reagent interactions can be estimated using a bonding criterion. 

Surfactant adsorption on saltlike minerals, such as calcite and dolomite, is a more complex process and is less understood than adsorption on oxide surfaces. These minerals are relatively soluble and when in contact with an aqueous medium develop an interfacial region of complex composition (41—43). In addition to the two mentioned mechanisms of adsorption, covalent bonding, salt formation between surfactant and lattice ions at the solid surface, ion exchange of surfactant with lattice ions, and surface precipitation have been suggested as adsorption mechanisms (36, 43—47). The dissolution products of sparingly soluble minerals may interact with the surfactant, precipitate or adsorb at the solid surface, or lead to mineral transformations that affect surface composition and electrochemical properties (46, 48—52). All these factors can be expected to influence surfactant adsorption. 

Etschmann BE, Maslen EN (2000) Atomic radii from electron densities. Aust J Phys 53 317-332 Feth S, Gibbs GV, Boisen MB, Hill FC (1998) A study of the bonded interactions in nitride molecules in terms of bond critical point properties and relative electronegativities. Phys Chem Miner 98 234-241... 

Kirfel A, Lippmann T, Blaha P et al (2005) Electron density distribution and bond critical point properties for forsterite, Mg2Si04. Phys Chem Miner 32 301-313 Gibbs GV, Downs RT, Cox DF et al (2008) Experimental bond critical point and local energy density properties determined for Mn-O, Fe-O, and Co-O bonded interactions for tephroite, Mn2Si04, fayalite, Fe2Si04, and olivine, Co2Si04 and selected organic metal complexes. J Phys Chem Al 12 8811-8823... 

Gibbs GV, Boisen MB Jr, Hill FC et al (1998) SiO and GeO bonded interactions as inferred from the bond critical point properties of electron density distributions. Phys Chem Miner 25 574-584... 

In previous chapters, the main modes of interaction between ions and soil mineral colloids have been discussed in Chapters 4 and 5, the principles of ion-surface interactions have been laid down, and in Chapters 8 and 9, the main features of adsorption onto silicate and oxide minerals have been reviewed. As introduced in Chapter 11, two main contributions should be considered, namely, the nonelectrostatic forces composed of physical (van der Waals forces) and/or chemical (specific bonding) interactions and the electrostatic forces arising from the charged nature of both the adsorbate and the surface this is reflected in two contributions (considered independent) to the Gibbs free energy, as in Equation 11.5 ... 

When the electric field of the radiation interacts with the electron cloud of the mineral bond, it induces a dipole moment m in that bond that is given by... 

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