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A Lattice Energy Spreadsheet is a tool that easily calculates lattice energies. It also illustrates the relation between crystal structure, coordination number, and ionic radii. A Lattice Energy Spreadsheet contains five related worksheets: Lattice Energy, MX Structure Map, Kapustinsky Lattice Energy, Directions, and Discussion, each described below. In the Lattice Energy worksheet, the lattice energy of many binary compounds can be calculated in about a dozen mouse clicks. An element is selected, and the radius corresponding to the desired charge and coordination number is selected. The same is done for the counter ion, and the anticipated crystal structure of the compound is chosen (rock salt, wurtzite, etc.). The lattice energy is then calculated. This sheet uses enthalpies of formation of monatomic gaseous atoms from the elements, ΔH°form to calculate lattice energies. The results are more accurate than the values obtained by simply summing enthalpies of fusion and vaporization. The results of the corresponding Born–Haber cycle are also graphed on this sheet.
Born–Haber cycle plot for TiO from A Lattice Energy
Spreadsheet
A structure map is a plot of average principal quantum number versus difference in electronegativity. Compounds in the same region of such a plot tend to have the same type of crystal structure. In MX Structure Map, students or instructors select two elements making up a 1:1 compound. The spreadsheet locates the chosen compound on the structure map, allowing the compound’s structure to be predicted.
An MX structure map from A
Lattice Energy Spreadsheet
The Kapustinsky Lattice Energy worksheet has thermochemical radii of hundreds of anions and cations. Just select a compound’s anion and cation from a drop-down list, and the compound’s lattice energy, including estimated uncertainty, is calculated with the Kapustinsky equation! In the Directions worksheet, users find complete instructions and suggestions for using this spreadsheet, along with references to excellent Web sites on crystal structures. Discussion discusses the sources of much of the data used in the calculations and provides more details about how the calculations are made.
Try this spreadsheet for yourself first; then use it in a presentation in
your next inorganic chemistry course.
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