anionoidadj.

1925 A. Lapworth in Mem. & Proc. Manch. Literary & Philos. Soc. 69 p. xix, Some ions..are shown to have some properties in common and are termed ‘cationoid’... [Some] have other properties in common and are termed ‘anionoid’.

1925 A. Lapworth in Mem. & Proc. Manch. Literary & Philos. Soc. 69 p. xix, The ‘anionoid’ properties of ethylenic hydrocarbons are held to be closely related to Thomson's observation that methyl is frequently observed in vacuum tubes with a positive charge, but never with a negative charge.

1936 Discovery May 162/2 The function of anionoid and kationoid reagents in ionic reactions.

1943 H. Gilman et al. Org. Chem. (ed. 2) II. xxv. 1859 The terms cationoid and anionoid..refer to the characteristic acceptor or donor activity of reactive cations or anions.

1953 C. K. Ingold Struct. & Mech. Org. Chem. v. 203 [Lapworth] likened all reagents either to anions or to cations: an ‘anionoid’ reagent was one which behaved analogously to an anion, or, as Robinson subsequently expressed it, to an ‘active’ anion; and a ‘cationoid’ reagent was one which behaved like a cation, or an active cation.

1958 J. Packer & J. Vaughan Mod. Approach Org. Chem. ii. 57, B is said to be electron-donating, anionoid (anionlike) or nucleophilic.