Electrochemistry of deposition of boron on a platinum electrode from KCl (81.54 mol%)-KF (18.45 mol%)-KBF 4 (1.6 to 7.73 × 10 −4 mol cm −3 ) melts was studied by cyclic voltammetry, chronoamperometry and convolution voltammetry. These studies were carried out over the temperature range 1073-1123 K. Boron-containing complexes are shown to reduce quasireversibly (scan rate: <0.1 V s −1 ) and irreversibly (scan rate: >0.1 V s −1 ) through a single-step three-electron process (B(III) + 3e → B). The transfer and diffusion coefficients were measured at different KBF 4 concentrations in the melt over the temperature range 1073-1123 K by using cyclic voltammetry, convolution voltammetry and chronoamperometry.