Complex ions in aqueous solution

In 2000, 108 Mt of gypsum was produced worldwide. Within the US in 2000, 22.9 Mt of prefabricated gypsum products were sold or used in the US, and the chart below shows the distribution of products making up this total. 

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Table 11. STABILITY OF COMPLEX IONS IN AQUEOUS SOLUTIONS...

Muha G.M., Vauoghan P.A. Structure of the complex ion in aqueous solutions of... 

First law of thermodynamics the energy of the universe is constant same as the law of conservation of energy. (9.1) Fission the process of using a neutron to split a heavy nucleus into two nuclei with smaller mass numbers. (21.6) Formal charge the charge assigned to an atom in a molecule or polyatomic ion derived from a specific set of rules. (13.12) Formation constant (stability constant) the equilibrium constant for each step of the formation of a complex ion by the addition of an individual ligand to a metal ion or complex ion in aqueous solution. (8.9)... 

The logical place to begin a discussion of the formation and stability of complex ions in aqueous solutions is with the aqueous ions themselves. If we regard the (metal) ion as being an aqueous complex (M(H20) )i , which is then further and more loosely solvated, we wish to know the coordination number n and also the manner in which the n molecules are arranged around the metal ion. 

Fig. 9.10 Mental model for complex ions in aqueous solution...

Complex ions in aqueous solution Complexes with amido or alkoxy ligands Diagonal relationships... 

In a fundamental sense metal ions simply dissolved in water are already complexed—they have formed aquo ions. The process of forming what we more conventionally call complexes is really one of displacing one set of ligands, which happen to be water molecules, by another set. Thus the logical place to begin a discussion of the formation and stability of complex ions in aqueous solution is with the aquo ions themselves. 

BON] Bond, A. M., Correlation of heterogenous charge-transfer rate constants and homogenous rate constants for removal of coordinated water in the AC and DC polarographic study of some irreversibly reduced complex ions in aqueous solution, J. Phys. Chem., 75, (1971), 2640-2649. Cited on pages 142, 143, 144, 148, 345. 

Formation constant (stability constant) the equilibrium constant for each step of the formation of a complex ion by the addition of an individual ligand to a metal ion or complex ion in aqueous solution. (8.9)... 

An assembly of a metal ion and the Lewis bases bonded to it, such as Ag(NH3)2, is called a complex ion. The stability of a complex ion in aqueous solution can be judged by the size of the equilibrium constant for its formation from the hydrated metal ion. For example, the equilibrium constant for Equation 17.24 is... 

The formation of complex ions in aqueous solutions with anionic ligands is an important feature of the aqueous chemistry of Pu. Complex formation and hydrolysis are competing reactions and may be looked upon as the displacement of the HgO molecules in the hydration sphere by the anionic ligand or by OH , respectively. The ability of an ion to form complexes is dependent on the magnitude of the ionic potential which may be defined by the equation... 

Jaques, A. Complex Ions in Aqueous Solutions Longmans London, England, 1914. 

Figure 9.9 Correlation of rate constants for electron-exchange reactions with molecular dimensions (1). The plot shows an inverse correlation of rate constant (k ) with diameter (2a) of reactant ions MLg, for electron-exchange reactions of a series of ruthenium complex ions in aqueous solution at 298 K. The plot is of [InCtobs/ a) (i-e-, hiiet) against l/2a. See text. Bond lengths ate assumed equal to those in crystals, determined by X-ray diffraction. The systems ate (1) Ru(NH3)g, (2) Ru(NH3)5(py) +/ +, (3) Ru(NH3)4(bpy) +/2+ (4) Ru(NH3)2(bpy)2 , (5) Rufbpylj. The figure is teptoduced from Ref. [16].

The term complexation refers to the reaction of a metal ion with an electron donor group (ligand), and entails the transformation of a solvated metal ion into a complex ion. In aqueous solutions of metal salts, the metal cations are surrounded by a sheath of aquo groups which are collectively called the primary hydration sphere. These solvated metal ions are not referred to as complex ions. Instead, a complex ion is formed if one or more of the solvent molecules within the primary hydration sphere of the metal ion is replaced either by ions, or by... 

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