A burner capable of burning hydrogen and fluorine as premixed reactants at low pressures is described. The construction of the burner was such that the reaction, which is normally considered spontaneous when the gases come in contact, remained suppressed until the lip of the burner was reached. Combustion occurred over an extremely wide range of fuel‐oxidant ratios including mixtures rich in fluorine. The flame produced by the burner was flat and symmetrical in shape.