pyrophoricadj.

1788 G. von Engestrom in J. H. de Magellan et al. Cronstedt's Ess. Syst. Mineral. (ed. 2) I. 397 Almost every substance which leaves, after its decomposition, a coaly matter, simply divided by an earth, or a metallic calx, possesses the same pyrophoric property.

1836 W. T. Brande Man. Chem. (ed. 4) 1119 A residue..which burns like tinder when heated, and at a high temperature is pyrophoric.

1876 J. Harley Royle's Man. Materia Med. (ed. 6) 247 At a higher temperature this is completely decomposed, leaving a pyrophoric mixture of lead and carbon.

1940 G. H. J. Adlam & L. S. Price Higher School Certificate Inorg. Chem. (ed. 2) liv. 567 Very finely divided cobalt, produced by reduction of the oxide at about 250° C., combines readily with oxygen and is pyrophoric.

1998 N. H. Harley et al. Depleted Uranium (National Defense Res. Inst.) p. xiii In addition to being very dense.., DU, like any uranium, is pyrophoric, that is, in fine particles it can ignite easily.

1906 C. A. von Welsbach U.S. Patent 837,017 What I claim is—1. A pyrophoric alloy, containing cerium alloyed with iron; substantially as and for the purposes described.

1934 Official Gaz. (U.S. Patent Office) 10 July 270 Zippo for pocket lighter of the pyrophoric type.

1950 Thorpe's Dict. Appl. Chem. (ed. 4) X. 328/2 The pyrophoric alloy, in the form of a small rod, is generally pressed firmly against a hard steel wheel with a roughened surface. The shower of sparks produced on rapidly rotating the wheel is projected on to a cotton wick impregnated with..lighter fluid.

1998 R. E. Krebs Hist. & Use our Earth's Chem. Elem. ix. 221 Misch metal..is pyrophoric, which means it sparks when scratched.