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Some chemistry textbooks [3] as well as the widely used CRC Handbook of Chemistry and Physics [4] define lattice energy with the opposite sign, i.e. as the energy required to convert the crystal into infinitely separated gaseous ions in vacuum, an endothermic process. Following this convention, the lattice energy of NaCl would be +786 kJ/mol.
where is the coordination number, the number of nearest neighbors for a lattice site, each one occupied either by one chain segment or a solvent molecule. That is, x N 2 {\displaystyle xN_{2}} is the total number of polymer segments (monomers) in the solution, so x N 2 z {\displaystyle xN_{2}z} is the number of nearest-neighbor sites to all the ...
The Born–Landé equation is a means of calculating the lattice energy of a crystalline ionic compound.In 1918 [1] Max Born and Alfred Landé proposed that the lattice energy could be derived from the electrostatic potential of the ionic lattice and a repulsive potential energy term.
Water of crystallization can generally be removed by heating a sample but the crystalline properties are often lost. Compared to inorganic salts, proteins crystallize with large amounts of water in the crystal lattice. A water content of 50% is not uncommon for proteins.
z + = charge number of cation; z − = charge number of anion; e = elementary charge, 1.6022 × 10 −19 C; ε 0 = permittivity of free space 4 π ε 0 = 1.112 × 10 −10 C 2 /(J·m) r 0 = distance to closest ion; ρ = a constant dependent on the compressibility of the crystal; 30 pm works well for all alkali metal halides
The calculated lattice energy gives a good estimation for the Born–Landé equation; the real value differs in most cases by less than 5%. Furthermore, one is able to determine the ionic radii (or more properly, the thermochemical radius) using the Kapustinskii equation when the lattice energy is known.
The electrostatic interaction model of ions in solids has thus been extended to a point multipole concept that also includes higher multipole moments like dipoles, quadrupoles etc. [8] [9] [10] These concepts require the determination of higher order Madelung constants or so-called electrostatic lattice constants.
Lanthanum oxide is a white solid that is insoluble in water, but dissolves in acidic solutions. La 2 O 3 absorbs moisture from air, converting to lanthanum hydroxide. [ 2 ] Lanthanum oxide has p-type semiconducting properties and a band gap of approximately 5.8 eV. [ 3 ]