| abstract |
The invention relates to a method for obtaining a magnesium fluoride (MgF 2 ) sol solution, comprising the steps of providing a magnesium precursor in a first volume in a non-aqueous solvent, and adding, in a second volume, 1.85 to 2.05 molar equivalents of anhydrous hydrogen fluoride (HF) per mole calcium precursor to said first volume, and adding a metal additive before, during or after step b), wherein said metal additive is calcium, in form of a calcium precursor, wherein the amount of said calcium additive, in relation to the amount of said magnesium precursor is 1 : 100 to 1 : 1, as measured in molar equivalents of said calcium additive to said magnesium precursor, and wherein additionally 1.85 to 2.05 molar equivalents of anhydrous hydrogen fluoride(n HFc ) per mole calcium additive is present in said second volume. |