Symbol Hi
Atomic number 166
Pronunciation /'higs•ē•(y)üm/
Named after Peter Higgs
Name in Saurian Xawwjaim (Xa)
Systematic name Unhexhexium (Uhh)
Location on the periodic table
Group 12
Period 8
Family Zinc family
Series Kelvinide series
Coordinate 7d10
Element above Higgsium Copernicium
Element left of Higgsium Becquerelium
Element right of Higgsium Kirchoffium
Atomic properties
Subatomic particles 650
Atomic mass 488.0544 u, 810.4333 yg
Atomic radius 178 pm, 1.78 Å
Covalent radius 156 pm, 1.56 Å
van der Waals radius 237 pm, 2.37 Å
Nuclear properties
Nucleons 484 (166 p+, 318 no)
Nuclear ratio 1.92
Nuclear radius 9.38 fm
Half-life 3.0228 min
Decay mode Spontaneous fission
Decay product Various
Electronic properties
Electron notation 166-9-25
Electron configuration [Og] 5g18 6f14 7d10 8s2 8p2 9s2
Electrons per shell 2, 8, 18, 32, 50, 32, 18, 4, 2
Oxidation states +1, +2, +4
(a strongly basic oxide)
Electronegativity 1.13
First ionization energy 628.6 kJ/mol, 6.515 eV
Electron affinity 47.2 kJ/mol, 0.489 eV
Physical properties
Bulk properties
Molar mass 488.054 g/mol
Molar volume 43.963 cm3/mol
Density 11.101 g/cm3
Atomic number density 1.23 × 1021 g−1
1.37 × 1022 cm−3
Average atomic separation 418 pm, 4.18 Å
Speed of sound 1458 m/s
Magnetic ordering Diamagnetic
Crystal structure Hexagonal
Color Peach
Phase Solid
Thermal properties
Melting point 1203.56 K, 2166.40°R
930.41°C, 1706.73°F
Boiling point 1602.65 K, 2884.77°R
1329.50°C, 2425.10°F
Liquid range 399.10 K, 718.37°R
Liquid ratio 1.33
Triple point 1203.54 K, 2166.38°R
930.39°C, 1706.71°F
@ 4.6955 kPa, 3473.6 torr
Critical point 3828.79 K, 6891.82°R
3555.64°C, 6432.15°F
@ 77.4015 MPa, 763.896 atm
Heat of fusion 14.032 kJ/mol
Heat of vaporization 127.902 kJ/mol
Heat capacity 0.04331 J/(g•K), 0.07795 J/(g•°R)
21.136 J/(mol•K), 38.044 J/(mol•°R)
Abundance in the universe
By mass Relative: 1.25 × 10−30
Absolute: 4.19 × 1022 kg
By atom 6.73 × 10−32

Higgsium is the provisional non-systematic name of a theoretical element with the symbol Hi and atomic number 166. Higgsium was named in honor of Peter Higgs (1929–), who predicted the existence of Higgs boson (the God particle) before it was discovered. This element is known in the scientific literature as unhexhexium (Uhh), dvi-mercury, or simply element 166. Higgsium is the heaviest member of the zinc family (below zinc, cadmium, mercury, and copernicium) and is the last member of the kelvinide series; this element is located in the periodic table coordinate 7d10.

Atomic properties Edit

Higgsium contains 166 electrons in 9 energy levels, averaging about 19 electrons per energy level. Due to extreme relativistic effects causing smearing of the orbitals, the electrons have completed the s-orbital in the ninth and outermost shell without completing the p-orbital first. However, there are two electrons in the p-orbital that was last added 39 elements ago. The electrons are full in the p1/2 split orbital and none in the p3/2 split orbital. Electrons make up only a tiny proportion of the atom's mass as almost all of its mass are protons and neutrons that make up the nucleus around which the electrons orbit.

Isotopes Edit

Like every other element heavier than lead, higgsium has no stable isotopes. The longest-lived isotope is 484Hi with a half-life of 3 minutes. It undergoes spontaneous fission, splitting into three lighter nuclei plus neutrons like the example.

Hi → 197
Au + 132
Xe + 75
As + 80 1

Higgsium has one meta state that is longer-lived than the most stable ground state isotope: 481m1Hi (half-life: 5 minutes). Other meta states include 483m1Hi (half-life: 3 seconds) and 485m2Hi (half-life: 178 milliseconds).

Chemical properties and compounds Edit

Higgsium is a reactive metal and tends to give up two electrons during chemical reactions, but it can also give up four electrons because in addition to electrons in the 9s orbital, the 8p1/2 orbital can also participate in bonding due to small spacing between the 8p1/2 and 9s orbitals. Higgsium(II) has chemical properties similar to calcium, found in salts like higgsium oxide (HiO) and higgsium carbonate (HiCO3), whereas higgsium(IV) would behave like tin or lead. This element forms solution which behave like calcium in its +2 state; its hydroxide (Hi(OH)2) is homologous to Ca(OH)2.

Higgsium can form compound anions such as HiF2−
, HiSO4−
, and HiCS4−

Higgsium can form numerous compounds. Higgsium(II) oxide (HiO) or higgsium(IV) oxide (HiO2) form when the metal exposes to air for a short time. Higgsium(II) sulfide (HiS) is a purple powder. Higgsium(II) chloride (HiCl2) forms when higgsium(II) perchlorate (Hi(ClO4)2) decomposes by heat, liberating oxygen in the process. HiCl2 can then react with chlorine gas to give HiCl4. Higgsium(II) bromide is formed when HiS reacts with silver(II) bromide (AgBr2).

HiS + AgBr2 → HiBr2 + AgS

The other bromide, HiBr4, is unstable unlike HiCl4. HiI2 would be the only iodide of higgsium.

Higgsium(II) carbonate (HiCO3), higgsium(II) sulfate (HiSO4), and higgsium(II) phosphate (Hi3(PO4)2) formed when higgsium reacts with carbonic acid, sulfuric acid, and phosphoric acid, respectively. Higgsium(II) hydride (HiH2) is formed when higgsium reacts directly with hydrogen gas or by extracting hydrogen from steam in the presence of carbon.

Higgsocene (C8H8Hi) is one example of organohiggsium.

Physical properties Edit

Higgsium's melting point is 1204 K (1707°F), which is the highest of any other element in the zinc group. Its boiling point is 399 K (718°F) higher than its melting point, similar to mercury's in liquid range. Its density is 11.1 g/cm3, halfway between that of cadmium (8.7 g/cm3) and mercury (13.5 g/cm3).

Electrons between the incompleted 8p orbital and full 9s orbital would exchange energies with each other at few specified wavelengths, mainly in the yellow, orange and green regions of the spectrum from about 550 nm to about 600 nm. Oscillations at multiple wavelengths simultaneously would make the metal appear peach instead of silvery unlike other metals in the zinc family.

Like other zinc family elements, higgsium is diamagnetic, meaning this element can repel magnetic field, thus causing levitation, at least to a very small degree.

Occurrence Edit

It is almost certain that higgsium 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 higgsium in the universe by mass is 1.25 × 10−30, which amounts to 4.19 × 1022 kilograms or about the twice the mass of Neptune's largest moon Triton worth of higgsium.

Synthesis Edit

To synthesize most stable isotopes of higgsium, 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, 484Hi.

Cf + 166
Er + 67 1
n → 484
Og + 114
Cd + 57 1
n → 484
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 Ts Og
8 Nw G Ls Dm Ms T Dt Mw Pk By Bz Fn Dw To Pl Ah My Cv Fy Chd A Ed Ab Bu 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
9 Me Jf Ul Gr Mr Arm Hy Ck Do Ib Eg Af Bhz Me Zm Qtr Bhr Cy Gt Lp Pi Ix El Sv Sk Abr Ea Sp Ws Sl Jo Bl Et Ci Ht Bp Ud It Yh Jp Ha Vi Gk L Ko Ja Ph Gv Dc Bm Jf Km Oc Lb
10 Io Ly