Magnesium lattice energy calculations

C03 (g). The lattice energy calculations of Lennard-Jones and Dent1, 2 on the carbonates of zinc, cadmium, calcium, and magnesium yield, for C03 (g), Qf = — 75 10. 

Compounds of aluminium and magnesium in the lower oxidation states, A1(I) and Mg (I), do not exist under normal conditions. If we make an assumption that the radius of AF or Mg is the same as that of Na (same row of the Periodic Table), then we can also equate the lattice energies, MCI. Use this information in a Born-Haber cycle to calculate... 

The lattice energy of magnesium bromide, MgBr, can be calculated using the enthalpy changes shown in the table. 

Calculations of the interaction energy in very fine pores are based on one or other of the standard expressions for the pair-wise interaction between atoms, already dealt with in Chapter 1. Anderson and Horlock, for example, used the Kirkwood-Miiller formulation in their calculations for argon adsorbed in slit-shaped pores of active magnesium oxide. They found that maximum enhancement of potential occurred in a pore of width 4-4 A, where its numerical value was 3-2kcalmol , as compared with 1-12, 1-0 and 1-07 kcal mol for positions over a cation, an anion and the centre of a lattice ceil, respectively, on a freely exposed (100) surface of magnesium oxide. 

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