Solid substances consisting of atoms, ions, or molecules that are arranged in a highly ordered microscopic structure, forming a crystal lattice that periodically extends in all directions in space, are called crystalline solids or crystals. X-ray diffraction is an analytical technique that gives information about the crystal structure, it is chemical composition, and physical characteristics of the crystal. Born- Haber circular process is used to calculate the crystal lattice energy. This method is based on Hess's law, which states that during the transition of a chemical system from one state to another, the total released energy does not depend on the reaction path. The total energy of the crystal lattice includes the enthalpies of all processes that take place during the formation of crystals from elements, namely: ionization energy, electron affinity, dissociation energy, and sublimation energy. In the first part of this work, crystal systems and their distribution according to Bravis are described, and how crystal structure is determined by diffraction. It also explains how to theoretically determine the energy of the crystal lattice and how it is related to the Born- Lande equation, the Kapustinski equation, the Madelung constant, and the Born- Haber cycle. In the second part of this work, determination of the crystal lattice energy using Crystal Explorer program is presented. In the aforementioned program, the energy of the crystal lattice was calculated for several dialdehyde compounds.