Symbol Sh
Atomic number 144
Pronunciation /'shēl•ē•(y)üm/
Named after Carl Wilhelm Scheele
Name in Saurian Jsxoocaim (Jx)
Systematic name Unquadquadium (Uqq)
Location on the periodic table
Period 8
Family Cerium family
Series Dumaside series
Coordinate 6f2
Element above Scheelium Thorium
Element left of Scheelium Dumasium
Element right of Scheelium Heisenbergium
Atomic properties
Subatomic particles 539
Atomic mass 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
Nuclear properties
Nucleons 395 (144 p+, 251 no)
Nuclear ratio 1.74
Nuclear radius 8.77 fm
Half-life 179.31 ms
Decay mode Spontaneous fission
Decay product Various
Electronic properties
Electron notation 144-8-24
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)
Electronegativity 1.71
First ionization energy 714.7 kJ/mol, 7.407 eV
Electron affinity 67.3 kJ/mol, 0.698 eV
Physical properties
Bulk properties
Molar mass 398.302 g/mol
Molar volume 39.521 cm3/mol
Density 10.078 g/cm3
Atomic number density 1.51 × 1021 g−1
1.52 × 1022 cm−3
Average atomic separation 403 pm, 4.03 Å
Speed of sound 3013 m/s
Magnetic ordering Paramagnetic
Crystal structure Cubic
Color Brownish gray
Phase Solid
Thermal properties
Melting point 821.40 K, 1478.52°R
548.25°C, 1018.85°F
Boiling point 3398.15 K, 6116.66°R
3125.00°C, 5656.99°F
Liquid range 2576.75 K, 4618.15°R
Liquid ratio 4.14
Triple point 821.50 K, 1478.69°R
548.35°C, 1019.02°F
@ 57.853 pPa, 4.3394 × 10−13 torr
Critical point 8233.86 K, 14820.96°R
7960.71°C, 14361.29°F
@ 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•K), 0.08892 J/(g•°R)
19.677 J/(mol•K), 35.418 J/(mol•°R)
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.

Isotopes Edit

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.

Sh → 222
Rn + 140
Ce + 33 1

Scheelium, like every transcalcium elements, has meta states. The longest-lived is 397m1Sh, whose half-life is 2.5 seconds, and 394mSh has a half-life of 1.8 seconds.

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−
(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.

Occurrence Edit

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 15 Pluto masses worth of scheelium.

Synthesis Edit

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.

At + 141
Pr + 44 1
n → 395
Mt + 80
Br + 28 1
n → 395
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
1 H He
2 Li Be B C N O F Ne
3 Na Mg Al Si P S Cl Ar
4 K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr
5 Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe
6 Cs Ba La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn
7 Fr Ra Ac Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr Rf Db Sg Bh Hs Mt Ds Rg Cn Nh Fl Mc Lv Tn Og
8 Nw G * Du Sh Hb Da Bo Fa Av So Hr Wt Dr Le Vh Hk Ke Ap Vw Hu Fh Ma Kp Gb Bc Hi Kf Bn J Hm Bs Rs
* Ls Dm Ms Ts Dt Mw Pk By Bz Fn Dw To Pl Ah My Cv Fy Ch A Ed Ab Bu

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