Double salts are salts containing more than one cation or anion, obtained by combination of two different salts which were crystallized in the same regular ionic lattice. Examples of double salts include alums (with the general formula MIMIII[SO4]2•6H2O) or Tutton salts (with the general formula [MI]2MII[SO4]2•6H2O). Other examples are potassi... Found on http://en.wikipedia.org/wiki/Double_salt
A salt in which two different positive ions are bonded to the same negative ion, or vice versa; e.g., NaKSO4. ... (05 Mar 2000) ... Found on http://www.encyclo.co.uk/local/20973