**Extensions**

Although copernicium is the heaviest known group 12 element, there has been some theoretical work regarding possible heavier group 12 elements. Although a simple extrapolation of the periodic table would put element 162, unhexbium (Uhb), under copernicium, relativistic Dirac-Fock calculations predict that the next group 12 element after copernicium should actually be element 164, unhexquadium (Uhq), which is predicted to have an electron configuration of 5g18 6f14 7d10 8s2 8p_{1/2}2. The 8s and 8p_{1/2} orbitals are predicted to be so strongly stabilized relativistically that they become core electrons and do not participate in chemical reactions, unlike the earlier group 12 elements where the s electrons behave as valence electrons. However, the 9s and 9p_{1/2} levels are expected to be readily available for hybridization and bonding, so that unhexquadium should still behave chemically like a normal transition metal. Calculations predict that the 7d electrons of unhexquadium should participate very readily in chemical reactions, so that unhexquadium should be able to show +6 and +4 oxidation states in addition to the normal +2 state in aqueous solutions with strong ligands. Unhexquadium should thus be able to form compounds like Uhq(CO)_{4}, Uhq(PF_{3})_{4} (both tetrahedral), and Uhq(CN)2−

2 (linear), which is very different behavior from that of lead, which unhexquadium would be a heavier homologue of if not for relativistic effects. Unhexquadium should be a soft metal like mercury, and metallic unhexquadium should have a high melting point as it is predicted to bond covalently. It should also have some similarities to ununoctium as well as to the other group 12 elements.

Read more about this topic: Group 12 Element

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### Famous quotes containing the word extensions:

“The psychological umbilical cord is more difficult to cut than the real one. We experience our children as *extensions* of ourselves, and we feel as though their behavior is an expression of something within us...instead of an expression of something in them. We see in our children our own reflection, and when we don’t like what we see, we feel angry at the reflection.”

—Elaine Heffner (20th century)

“If we focus exclusively on teaching our children to read, write, spell, and count in their first years of life, we turn our homes into *extensions* of school and turn bringing up a child into an exercise in curriculum development. We should be parents first and teachers of academic skills second.”

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