![]() ![]() It means that there is no formula for calculating the lattice energy of a compound based on given values, and it can only be derived after multiple laboratory calculations and experiments. One thing that should be noted here is that the lattice energy of any compound cannot be calculated directly. ![]() The lattice energy of an ionic compound is also helpful in providing some basic insights into the several properties of the compound, such as solubility, visibility, and many others. This also holds true in the opposite cases lower the amount of lattice energy required, weaker the bond strength of ionic compounds. If an ionic compound requires greater lattice energy to convert compound into gaseous ions, it means that the strength of ionic bonds in these compounds is very much stronger. Introduction to Lattice EnergyĪccording to the classical definition given in chemistry, "Lattice energy is the total amount of energy required for breaking or converting one mole of aqueous ionic compounds into one mole of ions." That's how lattice energy is used as a quantity that can tell us about the strength of bonds in the ionic compounds. Note: Stereochemistry: It is a sub-discipline of the chemistry branch which deals and talks about the formation of atoms & molecules and their spatial arrangements under various environments & reactions. This article talks about the basic concepts of lattice energy, attributes of lattice energy, and factors affecting lattice energy. Therefore, studying this topic becomes a must while learning the chemistry of compounds and reactions, and it should also not be left uncovered while working on ionic compounds in the laboratory. Lattice energy is not a complex or big topic, but it is important to be covered while studying ionic compounds or thermodynamics in chemistry. Therefore, calculating the lattice energy of ionic compounds becomes important, and it should be provided while dealing with many chemical compounds in a laboratory. This term is also used in thermodynamics to find out how a compound or chemical reaction can reach its equilibrium state without affecting the Stereochemistry of the compound. U = (–411.3) – (108.7 + 495.The lattice energy, a topic of chemistry and thermodynamics, is a term used to define the ion strength of the ionic compounds, including both alkali and alkaline type compounds. ΔH 3 = dissociation energy of Cl 2(S) = 244 kJ mol –1 ΔH 2 = ionisation energy of Na(S) = 495.0 kJ mol –1 ![]() ΔH 1 = heat of sublimation of Na(S) = 108.7 kJ mol –1 ΔH f = heat of formation of sodium chloride = – 411.3 kJ mol –1 Let us calculate the lattice energy of sodium chloride using Born-Haber cycle The sum of the enthalpy changes of these steps is equal to the enthalpy change for the overall reaction from which the lattice enthalpy of NaCl is calculated. Also, the formation of NaCl can be considered in 5 steps. Since the reaction is carried out with reactants in elemental forms and products in their standard states, at 1 bar, the overall enthalpy change of the reaction is also the enthalpy of formation for NaCl. Let us use the Born - Haber cycle for determining the lattice enthalpy of NaCl as follows: ˆ†H f - enthalpy change for the formation of solid MX directly form elements According to Hess's law of heat summation U - the lattice enthalpy for the formation of solid MX ˆ†H 3- Ionisation energy for M(g) to M +(g) ∆H 4 - electron affinity for the conversion of X(g) to X -(g) ΔH 2- enthalpy change for the dissociation of ½ X 2 (g) to X(g) ˆ†H 1 - enthalpy change for the sublimation M(s) to M(g) For example consider the formation of a simple ionic solid such as an alkali metal halide MX, the following steps are considered. The Born–Haber cycle applies Hess's law to calculate the lattice enthalpy. The cycle is concerned with the formation of an ionic compound from the reaction of a metal with a halogen or other non-metallic element such as oxygen.īorn–Haber cycle is primarily used in calculating lattice energy, which cannot be measured directly. It was named after two German scientists Max Born and Fritz Haber who developed this cycle. The Born–Haber cycle is an approach to analyse reaction energies.
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