by the formation of oxyanions; it forms anionic bismuthates in strongly basic solutions. Bismuth forms Zintl phases such as NaBi, Rb7In4Bi6 and Ba11Cd8Bi14. Bailar et al. refer to bismuth as being, 'the least "metallic" metal in its physical properties' given its brittle nature (and possibly) 'the lowest electrical conductivity of all metals.' Moscovium is expected to be a quite reactive metal. A standard reduction potential of −1.5 V for the Mc+/Mc couple is expected. This increased reactivity is consistent with the quasi-closed shell of flerovium and the beginning of a new series of elements with the filling of the loosely bound 7p3/2 subshell, and is rather different from the relative nobility of bismuth. Like thallium, moscovium should have a common +1 oxidation state and a less common +3 oxidation state, although their relative stabilities may change depending on the complexing ligands or the degree of hydrolysis. Moscovium(I) oxide (Mc2O) should be quite basic, like that of thallium, while moscovium(III) oxide (Mc2O3) should be amphoteric, like that of bismuth. Group 16 Selenium is a soft (MH 2.0) and brittle semi-metallic element. It is commonly regarded as a nonmetal, but is sometimes considered a metalloid or even a heavy metal. Selenium has a hexagonal polyatomic (CN 2) crystalline structure. It is a semiconductor with a band gap of 1.7 eV, and a photoconductor meaning its electrical conductivity increases a million-fold when illuminated. Selenium forms covalent bonds with most other elements, noting it can form ionic selenides with highly electropositive metals. The common oxide of selenium (SeO3) is strongly acidic. Selenium forms a series of anionic selenites and selenates such as Na2SeO3, Na2Se2O5, and Na2SeO4, as well as Zintl phases such as Cs4Se16. Tellurium is a soft (MH 2.25) and brittle semi-metallic element. It is commonly regarded as a metalloid, or by some authors either as a metal or a non-metal. Tellurium has a polyatomic (CN 2) hexagonal crystalline structure. It is a semiconductor with a band gap of 0.32 to 0.38 eV. Tellurium forms covalent bonds with most other elements, noting it has an extensive organometallic chemistry and that many tellurides can be regarded as metallic alloys. The common oxide of tellurium (TeO2) is amphoteric. Tellurium forms a series of anionic tellurites and tellurates such as Na2TeO3, Na6TeO6, and Rb6Te2O9 (the last containing tetrahedral and trigonal bipyramidal anions), as well as Zintl phases such as NaTe3. Polonium is a radioactive, soft metal