CAt4. At− anions have been reported to form astatides with silver, thallium, palladium and lead. Pruszyński et al. note that astatide ions should form strong complexes with soft metal cations such as Hg2+, Pd2+, Ag+ and Tl3+; they list the astatide formed with mercury as Hg(OH)At. Tennessine, despite being in the halogen column of the periodic table, is expected to go even further towards metallicity than astatine due to its small electron affinity. The −1 state should not be important for tennessine and its major oxidation states should be +1 and +3, with +3 more stable: Ts3+ is expected to behave similarly to Au3+ in halide media. As such, tennessine oxide (Ts2O3) is expected to be amphoteric, similar to gold oxide and astatine(III) oxide. Group 18 Oganesson is expected to be a very poor "noble gas" and may even be metallised by its large atomic radius and the weak binding of the easily removed 7p3/2 electrons: certainly it is expected to be a quite reactive element that is solid at room temperature and has some similarities to tin, as one effect of the spin–orbit splitting of the 7p subshell is a "partial role reversal" of groups 14 and 18. Due to the immense polarisability of oganesson, it is expected that not only oganesson(II) fluoride but also oganesson(IV) fluoride should be predominantly ionic, involving the formation of Og2+ and Og4+ cations. Oganesson(II) oxide (OgO) and oganesson(IV) oxide (OgO2) are both expected to be amphoteric, similar to the oxides of tin. Aliases and related groupings B-subgroup metals Superficially, the B-subgroup metals are the metals in Groups IB to VIIB of the periodic table, corresponding to groups 11 to 17 using current IUPAC nomenclature. Practically, the group 11 metals (copper, silver and gold) are ordinarily regarded as transition metals (or sometimes as coinage metals, or noble metals) whereas the group 12 metals (zinc, cadmium, and mercury) may or may not be treated as B-subgroup metals depending on if the transition metals are taken to end at group 11 or group 12. The 'B' nomenclature (as in Groups IB, IIB, and so on) was superseded in 1988 but is still occasionally encountered in more recent literature. The B-subgroup metals show nonmetallic properties; this is particularly apparent in moving from group 12 to group 16. Although the group 11 metals have normal close-packed metallic structures they show an overlap in chemical properties. In their +1