actinonn.

1920 E. Q. Adams in Jrnl. Amer. Chem. Soc. 42 2206 The names ‘radium emanation’, ‘actinium emanation’ and ‘thorium emanation’ have been shortened, respectively, to ‘radon’, ‘actinon’ and ‘thoron’, names which suggest that the element in question is an inert gas.

1938 R. W. Lawson tr. G. von Hevesy & F. A. Paneth Man. Radioactivity (ed. 2) xvii. 165 The molecular weight of the emanations (radon, thoron, actinon) can be approximately determined by observation of the velocity with which they flow through small orifices.

1959 Chambers's Encycl. XI. 484/2 Its [sc. radon's] isotopes thoron and actinon are also radioactive emanations.

2000 Microchem. Jrnl. 67 368/2 The radon ²²²Rn, thoron ²²⁰Th and actinon ²¹⁹Rn gases formed in the decay..escape through the pores of the soil.

1947 Q. Rev. Chem. Soc. 1 126 The term ‘lanthanon’ (Ln) is proposed to denote any element of the group from lanthanum to lutecium inclusive,..and to bring them into conformity with their new analogues the ‘actinons’.

1962 P. J. Durrant & B. Durrant Introd. Adv. Inorg. Chem. xxvi. 1130 The actinons are the elements following actinium in the seventh Period of the periodic table.

2006 N.Y. Times (Nexis) 24 Oct. f4 The most common rearrangement, a spiral, tries to illustrate hydrogen's relationship to multiple elements and to integrate a block of elements known as lanthanons and actinons.