Born–Haber cycle

The Born- Haber cycle ( after its developers Fritz Haber and Max Born) associated thermodynamic quantities ( state variables ). Each of the variables can be determined when the other are known.

Operation

In many cases, the schema for determining experimentally difficult to access electron affinities of is used. You can also make predictions about rates of previously unknown compounds, for example those with high oxidation numbers.

The noble gas compounds were predicted on stability estimates using the Born-Haber cycle process to be stable prior to their synthesis.

The Born- Haber cycle can also be used for the quantitative determination of ionic bonding in crystals. Example sodium chloride is often chosen in which the heat of reaction of solid sodium is measured by the gaseous chlorine.

The crystal is with the necessary energy ( lattice energy ) in Na - ions decomposed - and Cl. If the Na ions are converted into neutral sodium atoms, the ionization energy is free, while in the conversion of Cl - ions must be expended in energy neutral atoms (so-called electron affinity ). Is sodium from the vapor phase in the solid state, the sublimation is free and in the formation of chlorine molecules from the chloride atoms dissociation. The cycle is terminated by reaction of the solid sodium with the gaseous chlorine, in which the heat of reaction Q is released.