^ B(0) has been observed in diborynes, see Braunschweig, H.Chemical Structure and Reactivity: An Integrated Approach. ^ B(−1) has been observed in magnesium diboride (MgB 2), see Keeler, James Wothers, Peter (2014).'Eigenschaften von borreichen Boriden und Scandium-Aluminium-Oxid-Carbiden' (in German). ^ B(−5) has been observed in Al 3BC, see Schroeder, Melanie.'A Stable, Crystalline Beryllium Radical Cation'. Pan, Sudip Frenking, Gernot Gilliard Jr., Robert G. 'Infrared Emission Spectra of BeH and BeD' (PDF). ^ Be(I) has been observed in beryllium monohydride (BeH) see Shayesteh, A.^ Be(0) has been observed see 'Beryllium(0) Complex Found'.Physical Chemistry Chemical Physics (45). 'Structure and stability of small lithium-chloride Li nCl m (0,1+) (n ≥ m, n = 1–6, m = 1–3) clusters'. ^ Li(0) atoms have been observed in various small lithium-chloride clusters see Milovanović, Milan Veličković, Suzana Veljkovićb, Filip Jerosimić, Stanka (October 30, 2017).^ a b c d e Na(−1), K(−1), Rb(−1), and Cs(−1) are known in alkalides the table by Greenwood and Earnshaw shows −1 only for Na and also erroneously for Li no lithides are described.

'A stable compound of helium and sodium at high pressure'. Dronskowski, Richard Zhou, Xiang-Feng Prakapenka, Vitali B. Stavrou, Elissaios Lobanov, Sergey Saleh, Gabriele Qian, Guang-Rui Zhu, Qiang Gatti, Carlo Deringer, Volker L. ^ Disodium helide, (Na +) 2He(e -) 2, has been synthesized at high pressure, see Dong, Xiao Oganov, Artem R.

Oxidation chart periodic table