The chapter deals with the chemical compounds formed by the transition elements of the periodic system elements, i.e. d- and f-elements. All these elements are metals and many of them have valuable physical and chemical properties. In the transition elements, the electrons are filled the d- and f-orbital atoms. The filling of the energy levels of the orbitals should occur as the electron energy increases in accordance with the rules of Pauli and Hund. However, many of the transient elements fill electronic orbitals in violation of these rules. This chapter shows that these anomalies can be described by analytic relationships and they lead to an increase in the chemical and physical activity of the elements. It is shown that the molecules of most compounds with the participation of transition elements are of higher dimensionality, which must be taken into account when analyzing their properties.
TopTransitional Elements In The Biosphere
The transitional elements are d- and f-elements located in the table of Mendeleev between s - and p-elements (in s-elements are completed by electrons s-orbitals of the outer level, in p-elements are completed p-orbitals of the outer level). In the d-elements are completed d-orbitals of the pre-outer level, in the f-elements are completed f-orbitals of the pre-outer levels. All these elements form metals. They play a big role in the biosphere - the shell of the Earth, in which there are living organisms (Vernadsky, 2012). They are in the lithosphere, making up the bulk of minerals (Fersman, 1937). In living organisms, due to the biogenic migration of atoms, almost all elements that exist in the crust and water can be detected, including the transitional elements. Transitional elements are centers of biologically active enzymes and hormones, i.e. a small amount in the body, as trace elements, is extremely important for the activity of organisms. However, in the case of excess of the norm (biotic concentration), the transitional elements exhibit toxic properties. The most common transitional element in nature is iron 4.65%, the second element in prevalence is titanium 0, 61%. All the transition elements in order of decreasing their distribution in nature can be represented in the form of a series
Fe (4,65%), Ti (0,62), Mn (0,09%), Zr (0,017%), V (0,015%), Gr (8,3 10
-3%), Zn (8 10
-3%), Cu (4,7 10
-3%), Ce (4,5 10
-3%), Co (4 10
-3%), Nd (3,7 10
-3%), La (1,8 10
-3%), Ni (8 10
-4%), Th(8 10
-4%), Cd (8 10
-4%), Sc (6 10
-4%), Hf (3,2 10
-4%),U(2,5 10
-4%), Ta (2 10
-4%), Mo (10
-4%), Wo (10
-4%), Ag (7 10
-6%), Au (5 10
-6%),Hg (5 10
-6%), Pt (5 10
-7), Y (2,8 10
-7%), Rh (10
-7%), Re (7 10
-8%).
Iron and titanium are constantly in the human body. There are a lot of iron-containing enzymes that catalyze the processes of electron transfer in mitochondria. They are called cytochromes (Metzler, 1980). Cytochromes are ironporphyrins in which all orbitals of the iron ion are occupied by donor atoms of bioligands.
Titanium performs vital functions: catalyzes the synthesis of hemoglobin, increases erythropoiesis and immunogenesis. Titanium compounds accelerate the biosynthesis of amino acids, activate lipoxygenase activity, it increases resistance to various diseases. Titanium compounds are active regulators of free-radical processes and systems for utilization of active forms of oxygen. Other transitional elements also perform important functions in living organisms. For protein, fat and carbohydrate metabolism are necessary Fe, Co, Mn, Zn, Mo, V, B, W. In the synthesis of proteins involved Mg, Mn, Fe, Co, Cu, Ni, Gr; in hematopoiesis – Co, Ti, Cu, Mn, Ni, Zn; in the breath – Mg, Fe, Cu, Zn, Mn, Co.
All these important functions in living organisms are due to the electronic structure of the outer and pre-outer levels of atoms. This is due to the large number of electrons in the d- and f-orbitals and, as a consequence, greater possibilities for variations in their number. In addition, there are a large number of free quantum cells on these orbitals that allow the donor-acceptor chemical bond to be realized. All this makes it possible for these atoms to have many valence electrons and to provide a considerable number of coordination bonds in complex compounds.