Related Experiment Video
Updated: Jun 28, 2026
12:02
Determination of Thermodynamic Properties of Alkaline Earth-liquid Metal Alloys Using the Electromotive Force Technique
Published on: November 3, 2017
Stability constants of aluminium fluoride complexes.
1Department of Chemistry, Forsyth Dental Center, Boston, MA 02115, U.S.A.
Talanta
|September 1, 1971
Summary
This study quantifies aluminium fluoride complex formation, determining stability constants for mononuclear species at varying ionic strengths and temperatures. The research provides crucial data for understanding aluminium-fluoride interactions in solution.
Area of Science:
- Inorganic Chemistry
- Solution Chemistry
- Coordination Chemistry
Background:
- Aluminum fluoride complexes are significant in environmental and biological systems.
- Understanding the speciation of aluminum in the presence of fluoride is crucial for various applications.
- Previous studies have provided limited data on the formation constants of these complexes under varied conditions.
Purpose of the Study:
- To determine the formation constants of mononuclear aluminum fluoride complexes.
- To investigate the influence of ionic strength and temperature on complex formation.
- To establish accurate thermodynamic data for Al-F interactions.
Main Methods:
- Pointwise titrations of aluminum nitrate with sodium fluoride.
- Potentiometric measurements using quinhydrone and lanthanum fluoride electrodes.
- Calculation of formation constants using non-linear generalized least-squares and linear least-squares methods.
Main Results:
- Only mononuclear aluminum fluoride complexes were identified.
- Formation constants were determined at ionic strengths of 0.5, 0.2, 0.1, and 0.05 M at 25 and 37 °C.
- Logarithmic formation constants for AlF, AlF2, AlF3, and AlF4 at 25 °C were 6.69, 5.35, 3.68, and 2.75, respectively.
Conclusions:
- The study successfully quantified the stepwise formation of aluminum fluoride complexes.
- Ionic strength and temperature have a measurable effect on the stability of these complexes.
- The developed methodology provides a robust approach for determining formation constants in complex solution systems.
Related Concept Videos
01:09Complexation Equilibria: Factors Influencing Stability of Complexes
In complexation reactions, metal cations are the electron pair acceptors, and the ligands are the electron pair donors. The stability of the metal complexes depends primarily on the complexing ability of the central metal ion and the nature of the ligands. Generally, the complexing ability of the metal ion depends on the size and charge of the ion. As the metal ion size increases, the stability of the metal complexes decreases, provided that the valency of the metal ion and the ligands remain...
01:23Complexation Equilibria: Overview
Complexation reactions take place when dative or coordinate covalent bonds form between metal ions and ligands. The compounds formed in these reactions are called coordination compounds. The number of bonds formed between the metal ion and the ligands is called its coordination number. Generally, most metal ions in an aqueous solution are solvated by water molecules and thus exist as aqua complexes.
The equilibrium constant of the complexation reaction is represented as the formation constant...
The equilibrium constant of the complexation reaction is represented as the formation constant...
01:09Solubility Equilibria: Overview
When a substance such as sodium chloride is added to water, it dissolves, forming an aqueous solution. The extent of dissolution is called solubility. The process of dissolution can exist in equilibrium, just like other chemical processes. Solubility equilibria are also called precipitation equilibria because the process of solubility can be reversible. The reverse of the solubility process is called precipitation.
Solubility is important in biological and environmental processes. A notable...
Solubility is important in biological and environmental processes. A notable...
02:42Ionic Crystal Structures
Ionic crystals consist of two or more different kinds of ions that usually have different sizes. The packing of these ions into a crystal structure is more complex than the packing of metal atoms that are the same size.
Most monatomic ions behave as charged spheres, and their attraction for ions of opposite charge is the same in every direction. Consequently, stable structures for ionic compounds result (1) when ions of one charge are surrounded by as many ions as possible of the opposite...
Most monatomic ions behave as charged spheres, and their attraction for ions of opposite charge is the same in every direction. Consequently, stable structures for ionic compounds result (1) when ions of one charge are surrounded by as many ions as possible of the opposite...
01:09EDTA: Conditional Formation Constant
Each EDTA molecule has six binding sites: four carboxyl groups and two amino groups. The fully protonated form of EDTA is represented as H6Y2+. However, it can exist in different forms, H5Y+, H4Y, H3Y−, H2Y2−, and HY3−, depending on the pH of the solution. In very basic solutions with pH > 10.17, the fully deprotonated form, Y4−, is the predominant species that readily complexes with metal ions in a 1:1 ratio.
For the equilibrium reaction of the metal with the Y4− form of EDTA, the formation...
For the equilibrium reaction of the metal with the Y4− form of EDTA, the formation...
03:45Formation of Complex Ions
A type of Lewis acid-base chemistry involves the formation of a complex ion (or a coordination complex) comprising a central atom, typically a transition metal cation, surrounded by ions or molecules called ligands. These ligands can be neutral molecules like H2O or NH3, or ions such as CN− or OH−. Often, the ligands act as Lewis bases, donating a pair of electrons to the central atom. These types of Lewis acid-base reactions are examples of a broad subdiscipline called coordination...