|Named after||Carl Wilhelm Scheele|
|Name in Saurian|| Jsxoocaim (Jx)|
|Systematic name|| Unquadquadium (Uqq)|
|Location on the periodic table|
|Element above Scheelium||Thorium|
|Element left of Scheelium||Dumasium|
|Element right of Scheelium||Heisenbergium|
|398.3017 u, 661.3955 yg|
|Atomic radius||139 pm, 1.39 Å|
|Covalent radius||151 pm, 1.51 Å|
|van der Waals radius||177 pm, 1.77 Å|
|s||395 (144 p+, 251 no)|
|Electron configuration||[Og] 5g17 6f2 7d3 8s2 8p2|
|Electrons per shell||2, 8, 18, 32, 49, 20, 11, 4|
|Oxidation states|| +2, +3, +4, +6, +8|
(a mildly basic oxide)
|First ionization energy||714.7 kJ/mol, 7.407 eV|
|Electron affinity||67.3 kJ/mol, 0.698 eV|
|Molar mass||398.302 g/mol|
|Molar volume||39.521 cm3/mol|
|Atomic number density|| 1.51 × 1021 g−1|
1.52 × 1022 cm−3
|Average atomic separation||403 pm, 4.03 Å|
|Melting point|| 821.40 K, 1478.52°R|
|Boiling point|| 3398.15 K, 6116.66°R|
|Liquid range||2576.75 , 4618.15|
|Triple point|| 821.50 K, 1478.69°R|
@ 57.853 pPa, 4.3394 × 10−13 torr
|Critical point|| 8233.86 K, 14820.96°R|
@ 95.8976 MPa, 946.438 atm
|Heat of fusion||7.015 kJ/mol|
|Heat of vaporization||301.225 kJ/mol|
|Heat capacity|| 0.04940 J/(g• ), 0.08892 J/(g• )|
19.677 J/(mol• ), 35.418 J/(mol• )
|Abundance in the universe|
|By mass|| Relative: 7.11 × 10−32|
Absolute: 2.38 × 1021 kg
|By atom||4.69 × 10−33|
Scheelium is the provisional non-systematic name of a theoretical element with the symbol Sh and atomic number 144. Scheelium was named in honor of Carl Wilhelm Scheele (1742–1786), who discovered numerous chemical substances, including oxygen, molybdenum, tungsten, and chlorine. This element is known in the scientific literature as unquadquadium (Uqq), eka-thorium, or simply element 144. Scheelium is the second member of the dumaside series, found in the third row of f-block (below cerium and thorium); this element is located in the periodic table coordinate 6f2.
Atomic properties Edit
Scheelium contains 251 neutrons, all are found in the nucleus that make up a tiny portion of the atom, but it contains almost all of the atom's mass. Nucleus also contains protons that determines its atomic number. Its nuclear ratio is 1.74, determined by dividing neutrons by protons in the nucleus. Outside the nucleus, there are eight shells of electrons. Number of protons determine its atomic number while atomic number determines how many electrons the atom contains. Scheelium has the atomic radius, distance from center of nucleus to the outermost shell, of 151 picometers, but the atom's boundary is 20 pm beyond the outermost shell.
Even though the last g-block element was four elements ago, it has just completed the g-orbital at 18. There should be four electrons in the f-orbital according to the periodic table, but actually there's only one, because of the extreme spin-orbit coupling due to relativistic effects, three 'stray electrons' are in the d-orbital.
Like every other element heavier than lead, scheelium has no stable isotopes. The longest-lived isotope is 395Sh with a half-life of 179 milliseconds. It undergoes spontaneous fission (example equation below) about 58% of the times, while it undergoes cluster decay the other 42% of the times.
Chemical properties and compounds Edit
Since scheelium is located below thorium on the periodic table, it should have similar chemical behavior to thorium. Like thorium, scheelium exhibits a common oxidation state of +6, such as in homologous hexafluoride. Scheelium would then have higher electronegativity and higher ionization energies than thorium, making scheelium less reactive than thorium.
Sh4+ is pink while Sh6+ is dark yellow-orange in aqueous solutions. Scheelium can form ionic complexes, most prominantly ShO2−
3 (scheelate), such as found in SgShO3.
According to the common oxidation states mentioned, scheelium can mainly bond to elements by donating two or four electrons, such as in dihalides and tetrahalides, as well as in monochalcides and dichalcides.
Sheelium hexafluoride (ShF6) is a yellow ionic salt which can be converted to ShF8 (yellowish peach crystals) using hydrofluoric acid. Sheelium hexachloride (ShCl6) appears similar to ShF6, which can be converted to ShCl8 (similar in appearance to trifluoride) using hydrochloric acid. Other halides are ShBr2 (peach ionic salt), ShBr3 (white crystals), ShI2 (orange-peach ionic salt), and ShI3 (bluish white crystals).
At ordinary conditions, scheelium would take couple of months for it to be oxidized to ShO3 (blackish gray), which can be reduced to ShO2 (gray) using carbon monoxide. Scheelium has several of refractive compounds: ShC, Sh2C, Sh3B4, Sh3B2, and ShB. Scheelium can form subpnictides, such as Sh3N2 (blue), Sh3P2 (purple), and Sh3As2 (purplish black).
Scheelium can form organic compounds called organoscheelium, such as scheelocene ((C8H8)2Sh) and triphenyl scheelate ((OC6H5)3(ShO3)2).
Physical properties Edit
Scheelium is a brownish gray metal that is malleable, ductile, and lustrous. Its molar mass is 398 g/mol while its molar volume is 39.5 cm3/mol, corresponding to its density of 10.08 g/cm3. The atoms form cubic crystal structure and they are separated by an average of 403 pm (4.03 Å). At ordinary conditions, scheelium is in α form, transforms to β form at 211°C (728°R), and then to γ form just before its melting point at 511°C (1029°R). There are 15 sextillion atoms in one cubic centimeter. Scheelium is paramagnetic at ordinary conditions, but below −158°C (208°R), which is its Néel point, it is antiferromagnetic. The sound travels through the rod of metal at a shade over 3000 m/s.
Its melting point is 548°C (1479°R) and its boiling point is 3125°C (6117°R), corresponding to its liquid ratio of 4.14, determined by dividing boiling point by melting point in absolute temperature scale (in Rankine or Kelvin scale). The amount of energy needed to liquify the metal is 7 kJ/mol while to vaporize, it needs to absorb 301 kJ/mol. To solidify, it releases the same amount of energy as it is needed to liquify while to condense it releases the same as it requires to vaporize. Its specific heat capacity is 0.0494 J/(g•°C) (0.0889 J/(g•°R)). Scheelium has the triple point of 548°C (1479°R) and 58 picopascals while its critical point is 7961°C (14821°R) and 96 megapascals.
It is almost certain that scheelium 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 scheelium in the universe by mass is 7.11 × 10−32, which amounts to 2.38 × 1021 kilograms or nearly 1⁄5 Pluto masses worth of scheelium.
To synthesize most stable isotopes of scheelium, 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. Here's couple of example equations in the synthesis of the most stable isotope, 395Sh.