If NaCl is doped with 10–3 mol % of SrCl2, what is the concentration of cation vacancies?
NaCl is doped with 10−3 mol % of SrCl2. 100 moles of NaCl are doped with 0.001 moles of SrCl2. 1 mole of NaCl is doped with 1000.001=10−5 moles of SrCl2 or 105 moles of Sr2+ cations. One Sr2+ ion creates one cation vacancy. 10−5 moles of Sr2+ will create 10−5 moles of cation vacancies which correspond to 10−5×6.023×1023=6.023×1018 cation vacancies per mole of NaCl.
