S 1918 (OTTO) Sodium fluoborate, 97% Cas 13755-29-8 - used in fluxes, metal finishing and in plating circuits. S 1918 (OTTO) Sodium fluoborate, 97% Cas 13755-29-8 - used as a starting material in the preparation of ionic liquids as well as boron trifluoride. It acts as an efficient catalyst for the synthesis of 3,4-dihydropyrimidin-2(1H)-ones and thiones.