|Named after||Stephen Hawking|
|Name in Saurian|| Xunbadaim (Xb)|
|Systematic name|| Unpenthexium (Uph)|
|Location on the periodic table|
|Element above Hawkinium||Nobelium|
|Element left of Hawkinium||Vanthoffium|
|Element right of Hawkinium||Kelvinum|
|444.6902 u, 738.4254 yg|
|Atomic radius||134 pm, 1.34 Å|
|Covalent radius||142 pm, 1.42 Å|
|van der Waals radius||200 pm, 2.00 Å|
|s||441 (156 p+, 285 no)|
|Electron configuration||[Og] 5g18 6f13 7d3 8s2 8p2|
|Electrons per shell||2, 8, 18, 32, 50, 31, 11, 4|
|Oxidation states|| 0, +2, +3, +4, +6|
(a mildly acidic oxide)
|First ionization energy||396.9 kJ/mol, 4.113 eV|
|Electron affinity||21.6 kJ/mol, 0.224 eV|
|Molar mass||444.690 g/mol|
|Molar volume||17.438 cm3/mol|
|Atomic number density|| 1.35 × 1021 g−1|
3.45 × 1022 cm−3
|Average atomic separation||307 pm, 3.07 Å|
|Crystal structure||Face-centered cubic|
|Melting point|| 1040.32 K, 1872.57°R|
|Boiling point|| 3155.53 K, 5679.95°R|
|Liquid range||2115.21 , 3807.37|
|Triple point|| 1040.28 K, 1872.50°R|
@ 21.345 μPa, 1.6010 × 10−5 torr
|Critical point|| 9344.57 K, 16820.23°R|
@ 399.1525 MPa, 3939.341 atm
|Heat of fusion||9.548 kJ/mol|
|Heat of vaporization||306.519 kJ/mol|
|Heat capacity|| 0.05180 J/(g• ), 0.09324 J/(g• )|
23.035 J/(mol• ), 41.464 J/(mol• )
|Abundance in the universe|
|By mass|| Relative: 5.86 × 10−31|
Absolute: 1.96 × 1022 kg
|By atom||3.46 × 10−32|
Hawkinium is the provisional non-systematic name of a theoretical element with the symbol Hk and atomic number 156. Hawkinium was named in honor of Stephen Hawking (1942–2018), who made famous contributions to the understanding about black holes, including that black holes emit radiation called Hawking radiation, theoretical cosmology, and quantum gravity. This element is known in the scientific literature as unpenthexium (Uph), eka-nobelium, or simply element 156. Hawkinium is the last member of the dumaside series, found in the third row of f-block (below ytterbium and nobelium); this element is located in the periodic table coordinate 6f14.
Atomic properties Edit
Hawkinium atom masses 444.69 daltons, four times that of tin atom and twice that of radon atom. Almost all of atom's mass is in the tiny center where it contains about three quarters of all component particles. The remaining quarter are electrons orbiting the nucleus, there are 156 total, hence its atomic number. Despite it is the last element of the 14-element f-block series, this element has just 13 electrons in the f-orbital due to spin-orbit coupling. The atom sizes at 134 pm in radius, similar to zinc. However if atom is a hard sphere, its real size would be 149 pm.
Like every other element heavier than lead, hawkinium has no stable isotopes. The longest-lived isotope is 441Hk with a half-life of 533⁄5 seconds. It undergoes spontaneous fission, splitting into two or three lighter nuclei plus neutrons like the examples.
Like other elements, hawkinium contains several metastable isomers with the longest being 442mHk, whose half-life is 3.31 hours, 222 times longer than the most stable ordinary isotope.
Chemical properties and compounds Edit
Due to its completed f-orbital and number of electrons in the d-orbital consistent with what the periodic table expects, hawkinium would have similar chemical properties to lighter cogeners. However during chemical reactions, hawkinium gives up two electrons in the d-orbital instead of two in the s-orbital due to d-orbital having lower partial ionization energy than s-orbital due to relativistic effects. As a result, +2 is the most stable oxidation state, such as in binary chalcides.
Hawkinium chalcides are HkO (sky blue ionic crystals), HkS (peach crystals), HkSe (brown amorphous solid), HkTe (gray amorphous solid), and HkPo (reddish brown amorphous solid). In addition to chalcides, there are halides and pnictides, such as HkF2, HkCl2, HkBr2, HkI2, HkAt2, Hk3N2, Hk3P2, Hk3As2, Hk3Sb2, and Hk3Bi2.
Hawkinium salts include HkSO4, HkCO3, and Hk(NO3)2. Organic compounds of hawkinium (organohawkinium) include hawkinocene ((C5H5)2Hk), which is a blue crystalline solid, which chloridizes to hawkinocene dichloride ((C5H5)2HkCl2, which is a yellow crystalline solid.
Physical properties Edit
Hawkinium is a ductile, malleable, dense, silvery metal. It is slightly denser than nobelium (25.5 g/cm3 vs. 23.4 g/cm3) and the densest known naturally-occurring element (osmium). The atoms form face-centered cubic crystal structure and is paramagnetic. The sound travels through the metal at 3561 m/s.
Hawkinium's melting point is 1040 K, similar to nobelium, whose melting point is 1100 K. Its boiling point is 3156 K, much higher than nobelium's 899 Kare much lower due to closed electron shells. When dividing boiling and melting points on the absolute temperature scale, it would result in a liquid ratio of 3.03.
It is almost certain that hawkinium doesn't exist on Earth at all, but it is believe to barely exist somewhere in the universe due to its brief lifetime. Every element heavier than iron can only naturally be produced by exploding stars. But it is likely impossible for even the most powerful supernovae or most violent neutron star collisions to produce this element through r-process because there's not enough energy available or not enough neutrons, respectively, to produce this hyperheavy element. Instead, this element can only be produced by advanced technological civilizations, virtually accounting for all of its abundance in the universe. An estimated abundance of hawkinium in the universe by mass is 5.86 × 10−31, which amounts to 1.96 × 1022 kilograms, which is about 50% more abundance mass of hawkinium as the total mass of Pluto.
To synthesize most stable isotopes of hawkinium, nuclei of a couple lighter elements must be fused together, and right amount of neutrons must be seeded. This operation would be impossible using current technology since it requires a tremendous amount of energy, thus its cross section would be so low that it is beyond the technological limit. Even if synthesis succeeds, this resulting element would quickly undergo fission. Here's couple of example equations in the synthesis of the most stable isotope, 441Hk.