Ionic Atmosphere is a concept employed in Debye-Hückel theory which explains the

electrolytic conductivity Conductivity (or specific conductance) of an electrolyte solution is a measure of its ability to conduct electricity. The SI unit of conductivity is Siemens per meter (S/m). Conductivity measurements are used routinely in many industrial and ...

behaviour of solutions. It can be generally defined as the area at which a charged entity is capable of attracting an entity of the opposite charge.

Asymmetry, or relaxation effect

If an electrical potential is applied to an electrolytic solution, a positive ion will move towards the negative electrode and drag along an entourage of negative ions with it. The more concentrated the solution, the closer these negative ions are to the positive ion and thus the greater the resistance experienced by the positive ion. This influence on the speed of an ion is known as the "Asymmetry effect" because the ionic atmosphere moving around the ion is not symmetrical; the charge density behind is greater than in the front, slowing the motion of the ion. Laidler K.J. and Meiser J.H., ''Physical Chemistry'' (Benjamin/Cummings 1982) p.269 The time required to form a new ionic atmosphere on the right or time required for ionic atmosphere on the left to fade away is known as time of relaxation. The asymmetrization of ionic atmosphere does not occur in the case of

Debye Falkenhagen effect The debye (symbol: D) (; ) is a CGS unit (a non- SI metric unit) of electric dipole momentTwo equal and opposite charges separated by some distance constitute an electric dipole. This dipole possesses an electric dipole moment whose value is gi ...

due to

high frequency High frequency (HF) is the ITU designation for the range of radio frequency electromagnetic waves (radio waves) between 3 and 30 megahertz (MHz). It is also known as the decameter band or decameter wave as its wavelengths range from one to ten ...

dependence of conductivity.

Electrophoretic effect

This is another factor which slows the motion of

ion An ion () is an atom or molecule with a net electrical charge. The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by conve ...

s within a solution. It is the tendency of the applied potential to move the ionic atmosphere itself. This drags the solvent molecules along because of the attractive forces between ions and

solvent A solvent (s) (from the Latin '' solvō'', "loosen, untie, solve") is a substance that dissolves a solute, resulting in a solution. A solvent is usually a liquid but can also be a solid, a gas, or a supercritical fluid. Water is a solvent for ...

molecules. As a result, the central ion at the centre of the ionic atmosphere is influenced to move towards the pole opposite its ionic atmosphere. This inclination retards its motion.

Limits to the model

The model of ionic atmosphere is less adequate for concentrated ionic solutions near saturation. These solutions as well as

molten salt Molten salt is salt which is solid at standard temperature and pressure but enters the liquid phase due to elevated temperature. Regular table salt has a melting point of 801 °C (1474°F) and a heat of fusion of 520 J/g.< ...

s or

ionic liquid An ionic liquid (IL) is a salt in the liquid state. In some contexts, the term has been restricted to salts whose melting point is below a specific temperature, such as . While ordinary liquids such as water and gasoline are predominantly made of ...

s have a structure similar to the

crystalline lattice A crystal or crystalline solid is a solid material whose constituents (such as atoms, molecules, or ions) are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions. In addition, macros ...

where water molecules are located between ions.

References

{{Reflist Analytical chemistry Physical chemistry