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The Born–Haber cycle is an approach to analyze reaction energies. It was named after two German scientists, Max Born and Fritz Haber , who developed it in 1919. [ 1 ] [ 2 ] [ 3 ] It was also independently formulated by Kazimierz Fajans [ 4 ] and published concurrently in the same journal. [ 1 ]
A representation of Hess's law (where H represents enthalpy) Hess's law of constant heat summation, also known simply as Hess's law, is a relationship in physical chemistry and thermodynamics [1] named after Germain Hess, a Swiss-born Russian chemist and physician who published it in 1840.
For many substances, the formation reaction may be considered as the sum of a number of simpler reactions, either real or fictitious. The enthalpy of reaction can then be analyzed by applying Hess' law, which states that the sum of the enthalpy changes for a number of individual reaction steps equals the enthalpy change of the overall reaction.
The calculated lattice energy gives a good estimation for the Born–Landé equation; the real value differs in most cases by less than 5%. Furthermore, one is able to determine the ionic radii (or more properly, the thermochemical radius) using the Kapustinskii equation when the lattice energy is known.
In these cases the polarization energy E pol associated with ions on polar lattice sites may be included in the Born–Haber cycle. As an example, one may consider the case of iron-pyrite FeS 2 . It has been shown that neglect of polarization led to a 15% difference between theory and experiment in the case of FeS 2 , whereas including it ...
In some reactions between highly reactive metals (usually from Group 1 or Group 2) and highly electronegative halogen gases, or water, the atoms can be ionized by electron transfer, [16] a process thermodynamically understood using the Born–Haber cycle. [17] Salts are formed by salt-forming reactions. A base and an acid, e.g., NH 3 + HCl → ...
Haber, along with Max Born, proposed the Born–Haber cycle as a method for evaluating the lattice energy of an ionic solid. Haber has also been described as the "father of chemical warfare " for his work developing and deploying chlorine and other poisonous gases during World War I.
Fritz Haber (German: [ˈfʁɪt͡s ˈhaːbɐ] ⓘ; 9 December 1868 – 29 January 1934) was a German chemist who received the Nobel Prize in Chemistry in 1918 for his invention of the Haber process, a method used in industry to synthesize ammonia from nitrogen gas and hydrogen gas.