Application of basic chemical concepts to understanding the formation and transformation mechanisms of humic substances: A revue of publications and own experimental data

Fundamental concepts of coordination and organic chemistry and their possible applications to understanding the formation and transformation mechanisms of humic substances were considered. In accordance with the electronic concepts of interactions between inorganic and organic molecules, the ash elements should be considered as structural components of soil humus determining its transformation. An important role of reactions with the participation of nucleophilic (electron-donating) reagents, including inorganic anions, in the transformation of the humus-mineral system of an acid soil is shown. Anion reactions can involve not only metal atoms of humus-mineral complexes but also the C and P atoms of the functional groups of humus macroligands. These reactions determine the transformation of humus molecules related to the formation of migration-capable compounds and the formation of new functional groups in a humus macroligand. The role of iron and phosphorus in the implementation of different transformation pathways of humic substances is shown.