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Kirchoffium (167Kf)
Pronunciation /'kərsh•uf•ē•(y)üm/
Name in Saurian Bahsxevvaim (Bv)
Systematic name Unhexseptium (Uhs)
Location on the periodic table
Period 9
Coordinate 9p1
Above element Nihonium (113Nh)
Below element ––
Previous element Hubbium (166Hb)
Next element Bornium (168Bn)
Family Boron family (Icosagens)
Series Kirchoffide series
Atomic properties
Atomic mass 483.0102 u, 802.0573 yg
Atomic radius 158 pm, 1.58 Å
Van der Waals radius 208 pm, 2.08 Å
Subatomic particles 646
Nuclear properties
Nucleons 479 (167 p+, 312 n0)
Nuclear ratio 1.87
Nuclear radius 9.35 fm
Half-life 16.755 μs
Electronic properties
Electron notation 167-9-26
Electron configuration [Gb] 9s2 9p1
2, 8, 18, 32, 50, 32, 18, 4, 3
Oxidation states +1, +3, +5
(mildly basic oxide)
Electronegativity 1.31
First ionization energy 621.7 kJ/mol, 6.443 eV
Electron affinity 65.9 kJ/mol, 0.683 eV
Covalent radius 163 pm, 1.63 Å
Physical properties
Bulk properties
Molar mass 483.010 g/mol
Molar volume 28.6458 cm3/mol
Density 16.862 g/cm3
Atomic number density 1.25 × 1021 g−1
2.10 × 1022 cm−3
Average atomic separation 362 pm, 3.62 Å
Speed of sound 3577 m/s
Magnetic ordering Diamagnetic
Crystal structure Face centered cubic
Color Indigo
Phase Solid
Melting point 1403.63 K, 2526.53°R
1130.48°C, 2066.86°F
Boiling point 1345.14 K, 2421.25°R
1071.99°C, 1961.58°F
Liquid range −58.49 K, −105.28°R
Liquid ratio 0.96
Triple point 1403.62 K, 2526.52°R
1130.47°C, 2066.85°F
@ 750.31 kPa, 5627.8 torr
Critical point 3175.30 K, 5715.53°R
2902.15°C, 5255.86°F
@ 177.2426 MPa, 1749.254 atm
Heat of fusion 15.270 kJ/mol
Heat of vaporization 143.388 kJ/mol
Heat capacity 0.04740 J/(g•K), 0.08532 J/(g•°R)
22.896 J/(mol•K), 41.212 J/(mol•°R)
Universe (by mass) Relative: 2.89 × 10−45
Absolute: 9.68 × 107 kg

Kirchoffium is the fabricated name of a hypothetical element with the symbol Kf and atomic number 167. Kirchoffium was named in honor of Gustav Kirchoff (1824–1887), who contributed to the fundamental understanding of electrical circuits, spectroscopy, and the emission of black-body radiation by heated objects. This element is known in the scientific literature as unhexseptium (Uhs), dvi-thallium, or simply element 167. Kirchoffium is the heaviest icosagen and is the first member of the namesake kirchoffide series, placing this element at 9p1 coordinate on the periodic table.

Properties Edit

Physical Edit

Kirchoffium is diamagnetic, meaning that its magnetic field is activated when externally applied. It is an indigo metal with density approaching 20 g/cm3. The reason why this metal is indigo instead of gray-white typical of most metals is because the energy gap between ground states and lowest excited states is very narrow due to relativistic effects. It is so narrow that electrons oscillate in the indigo region of the visible spectrum.

The element sublimates at 1072°C (2421°R), which means at that temperature kirchoffium goes directly from solid to gas or back without becoming a liquid first. Liquid kirchoffium is nonexistent because our atmospheric pressure is not enough. Its liquid state exists at pressure at least 750 kPa, and our atmospheric pressure is just 101 kPa. At 750 kPa, its boiling point would be identical to its melting point at 1130°C (2527°R).

Kirchoffium has a face centered cubic crystal lattice.

Atomic Edit

Its electronegativity is 1.71 and has five valence electrons. After completing the 9s orbital, the electrons are filling the 9p orbital as if skipping all the blocks between s and p. In the nucleus, there are 479 particles (167 protons, 312 neutrons), corresponding to its mass number.

Isotopes Edit

Like every other element heavier than lead, kirchoffium has no stable isotopes. The most stable isotope is 479Kf with a brief half-life of about 16¾ microseconds. It undergoes spontaneous fission, splitting into three lighter nuclei plus neutrons like the example.

Kf → 205
Tl + 133
Cs + 69
Ga + 72 1

Kirchoffium has meta states, several are much longer lived than the most stable ground state isotope. The longest lived meta state is 474mKf with a half-life of 21 seconds, more than a million times longer than the most stable ground state isotope.

Chemical Edit

Kirchoffium should have chemical properties similar to thallium and nihonium according to the periodic trend. However, due to the outermost valence not similar to other boron family members, then its chemical properties can deviate from other members. Still, oxidation states of kirchoffium is not much different from other members. Like all other members except for the lighter cogener becquerelium, +3 is the most stable oxistate with +1 and +5 being less common. Kf3+ has a electron configuration of gibbium while Kf+ has an electron configuration of hubbium. Kirchoffium has similar first ionization energy to thallium (6.44 eV vs. 6.11 eV), but it is the most electropositive boron member. As a result, kirchoffium would behave chemically like a boron group. Like all other lighter cogeners, Kf can easily form binary pnictides, such as KfN, as well as polyicosagen pnictides like KfTlAs and KfBcTlN.

Compounds Edit

Kirchoffium(III) nitride (KfN) is a white crystalline solid which melts at 1170°C (2598°R), kirchoffium(III) phosphide (KfP) is a yellow crystalline solid, and kirchoffium(III) arsenide is an aqua green solid. It can form intericosagen compounds with kirchoffium, such as KfB, KfAl, and KfGa.

Kirchoffium don't just form pnictides and icosides, but also chalcides and halides, such as Kf2O3, Kf2Se, KfF5, KfCl3, and KfI.

Occurrence and synthesis Edit

It is almost certain that kirchoffium doesn't exist on Earth at all, but it is believe to exist somewhere in the universe, at least barely. Since every element heavier than lithium were produced by stars, then kirchoffium must be produced in stars, and then thrown out into space by exploding stars. But it is theoretically 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 virtually can only be made by advanced technological civilizations. An estimated abundance of Kirchoffium in the universe by mass is 2.89 × 10−45, which amounts to 9.68 × 107 kilograms or about the mass of the world's heaviest train.

To go along with other such civilizations, humans on Earth may eventually have the capability to synthesize kirchoffium. To synthesize most stable isotopes of kirchoffium, nuclei of a couple lighter elements must be fused together, and right amount of neutrons must be seeded. This operation would be extremely difficult since it requires a vast amount of energy and even if nuclei of this element were produced would immediately decay due to its brief half-life. Here's couple of example equations in the production of the most stable isotope, 479Kf.

Bk + 174
Yb + 58 1
n → 479
Db + 152
Sm + 55 1
n → 479
Periodic table
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 Bc Fl Lz Lv J Mc
8 Nw Gl * Du Bu Ab Sh Hi Da Bo Fa Av So Hr Wt Dr Le Vh Hk Ke Ap Vw Hu Fh Ma Kp Gb
9 Ps Hb Kf Bn Ju Hm Bs Rs
* Ls Dm Ms Ts Dt Mw Pk By Bz Fk Dw To Pl Ah My Cv Fy Ch An Ed

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