The lattice energy of an ionic solid is a measure of the strength of bonds in that ionic compound. It is usually defined as the enthalpy of formation of the ionic compound from gaseous ions and as such is invariably exothermic.
The experimental lattice energy of NaCl is −787 kJ/mol.
Some older textbooks define lattice energy as the energy required to convert the ionic compound into gaseous ions which is an endothermic process, and following this definition the lattice energy of NaCl would be +787 kJ/mol.
|Compound||Calculated Lattice Energy||Experimental Lattice Energy|
|NaCl||−756 kJ/mol||−787 kJ/mol|
|LiF||−1007 kJ/mol||−1046 kJ/mol|
|CaCl2||−2170 kJ/mol||−2255 kJ/mol|
From the Born-Landé equation it can be seen that the lattice energy of a compound is dependant on a number of factors
Barium oxide (BaO), for instance, which has the NaCl structure and therfore the same Madelung constant, has a bond radius of 275 picometers and a lattice energy of -3054 kJ/mol, while sodium chloride (NaCl) has a bond radius of 283 picometers and a lattice energy of -786 kJ/mol.
US Patent Issued to Lattice Energy on Feb. 22 for "Apparatus and Method for Absorption of Incident Gamma Radiation and Its Conversion to Outgoing Radiation at Less Penetrating, Lower Energies and Frequencies" (Massachusetts, Illinois Inventors)
Feb 23, 2011; ALEXANDRIA, Va., Feb. 23 -- United States Patent no. 7,893,414, issued on Feb. 22, was assigned to Lattice Energy LLC (Chicago)....