Metal-additive-catalysed radical-recombination rates in flames

Abstract Traces of the metals Mg, Ca, Sr, Ba, Cr, Mn, Sn, U have been shown to reduce excess free radical concentrations in H 2 + O 2 + N 2 flames. This is the first characterised effect of metal additives on the chemistry of the flame gases themselves. The phenomenon has been satisfactorily interpreted in terms of catalytic cycles involving metal oxide and hydroxides.