18) Place the following in order of increasing magnitude of lattice energy. CaO MgO SrS A) MgO < CaO < SrS B) SrS < MgO < CaO C) SrS < CaO < MgO D) CaO < MgO < SrS E) CaO < SrS < MgO Answer: C 19) Place the following in order of increasing magnitude of lattice energy. MgO LiI CaS
cohesive energy of the CaO crystal. Using ab-initio quantum chemical methods for evaluating individual increments, we obtain ∼ 80% of the difference between the experimental and Hartree-Fock cohesive ener-gies. Lattice constants corrected for correlation effects deviate by less than 1% from experimental values, in the case of MgO and CaO.
The changes in energy that occur during a chemical reaction can be seen by examining the changes in chemical bonding. This can be used to classify reactions as exothermic or endothermic.
CaO is Halite, Rock Salt structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Ca2+ is bonded to six equivalent O2- atoms to form a mixture of corner and edge-sharing CaO6 octahedra.