Oganesson (Og)

What we actually know

Unknown (predicted to be a noble gas). Everything below — every ring, every gauge, every number — comes from models of a nucleus that has existed for roughly seven hundred millionths of a second at a time. One isotope has ever been made. It was measured once.

Isotopes synthesised: Og-294
First produced: 2002
Facility: Joint Institute for Nuclear Research
Half-life of Og-294: ~0.7 ms

n1 2/2n2 8/8n3 18/18n4 32/32n5 32/32n6 18/18n7 8/8

Shell architecture

Bohr model

\textcolor{#6b7280}{[Rn]}\; \textcolor{#a855f7}{5_{f}^{14}}\; \textcolor{#22c55e}{6_{d}^{10}}\; \textcolor{#ef4444}{7_{s}^{2}}\; \textcolor{#3b82f6}{7_{p}^{6}}

The closed 7p⁶ shell is what makes oganesson a noble gas on paper. Relativistic effects at this mass stretch that shell far beyond xenon’s, and every model disagrees about how far.

Configuration: [Rn] 5f14 6d10 7s2 7p6
Valence electrons: 8 (7s² 7p⁶)
Oxidation states: 0, +2

Predicted physicals

Densityof 25 · table max

Melting pointof 4000 K · table max

Boiling pointof 6000 K · table max

Electronegativityof 4 · table max

The liquid window

Melting to boiling25 K

325 K melts25 K liquid350 K boils

A 25 K gap between melting and boiling is extraordinarily narrow — narrower than any element we have actually measured. If the prediction holds, oganesson is a solid that barely liquefies before it boils away.

Crystal structure

Face-Centered Cubic

Lattice constantsa = 1.00

Cell anglesα = β = γ = 90°

Coordination number12

Atoms per cell4

Atomic packing factor0.74

Unmeasured

Emission spectrumNever observed. No line list exists for oganesson.

AppearanceNever seen. Predicted solid, not the inert gas we expect.

Sample chemistryOne atom at a time, for 0.7 ms. No compounds isolated.

Wave function

\Psi_{\text{Og}} \approx \frac{1}{\sqrt{118!}} \det \left| \chi_1(\mathbf{r}_1) \dots \chi_{118}(\mathbf{r}_{118}) \right|

A 118-term Slater determinant. It has never been evaluated for a real atom, and probably never will be — the basis sets required do not exist.