Symbol Vh
Atomic number 155
Pronunciation /'vant•huf•ē•(y)üm/
Named after Jacobus Henricus van 't Hoff
Name in Saurian Ludkxevvaim (Lx)
Systematic name Unpentpentium (Upp)
Location on the periodic table
Period 8
Family Thulium family
Series Dumaside series
Coordinate 6f13
Element above Vanthoffium Mendelevium
Element left of Vanthoffium Lewisium
Element right of Vanthoffium Hawkinium
Atomic properties
Subatomic particles 595
Atomic mass 443.6824 u, 736.7519 yg
Atomic radius 124 pm, 1.24 Å
Covalent radius 132 pm, 1.32 Å
van der Waals radius 183 pm, 1.83 Å
Nuclear properties
Nucleons 440 (155 p+, 285 no)
Nuclear ratio 1.84
Nuclear radius 9.09 fm
Half-life 4.5790 ms
Decay mode Spontaneous fission
Decay product Various
Electronic properties
Electron notation 155-8-24
Electron configuration [Og] 5g18 6f12 7d3 8s2 8p2
Electrons per shell 2, 8, 18, 32, 50, 30, 11, 4
Oxidation states 0, +1, +2, +3, +4, +5
(a mildly basic oxide)
Electronegativity 2.38
First ionization energy 954.0 kJ/mol, 9.887 eV
Electron affinity 29.2 kJ/mol, 0.303 eV
Physical properties
Bulk properties
Molar mass 443.682 g/mol
Molar volume 26.119 cm3/mol
Density 16.987 g/cm3
Atomic number density 1.36 × 1021 g−1
2.31 × 1022 cm−3
Average atomic separation 351 pm, 3.51 Å
Speed of sound 2795 m/s
Magnetic ordering Paramagnetic
Crystal structure Trigonal
Color Lime green
Phase Solid
Thermal properties
Melting point 1548.37 K, 2787.07°R
1275.22°C, 2327.40°F
Boiling point 3694.19 K, 6649.54°R
3421.04°C, 6189.87°F
Liquid range 2145.82 K, 3862.47°R
Liquid ratio 2.39
Triple point 1548.36 K, 2787.05°R
1275.21°C, 2327.38°F
@ 7.3523 mPa, 5.5147 × 10−5 torr
Critical point 8988.59 K, 16179.46°R
8715.44°C, 15719.79°F
@ 1.4675 MPa, 14.483 atm
Heat of fusion 17.039 kJ/mol
Heat of vaporization 115.293 kJ/mol
Heat capacity 0.05056 J/(g•K), 0.09100 J/(g•°R)
22.431 J/(mol•K), 40.376 J/(mol•°R)
Abundance in the universe
By mass Relative: 5.00 × 10−33
Absolute: 1.68 × 1020 kg
By atom 2.96 × 10−34

Vanthoffium is the provisional non-systematic name of a theoretical element with the symbol Vh and atomic number 155. Vanthoffium was named in honor of Jacobus Henricus van 't Hoff (1852–1911), who made discoveries in chemical kinetics, chemical equilibrium, osmotic pressure, and stereochemistry. This element is known in the scientific literature as unpentpentium (Upp), eka-mendelevium, or simply element 155. Vanthoffium is the thirteenth member of the dumaside series, found in the third row of f-block (below thulium and mendelevium); this element is located in the periodic table coordinate 6f13.

Atomic properties Edit

Vanthoffium's nucleus comprises of 440 particles (155 protons, 285 neutrons), which together make up almost all of atom's mass packed into such a tiny portion of the atom in volume. The electron configuration and electrons per shell is not what the periodic table would tell because of the spin-orbit coupling due to relativistic effects. As it is the second-to-last element of the f-block series, it should need just one more electron for its orbital to be full, but an electron is missing due to spin-orbit coupling. The missing f-orbital electron belongs in the d-orbital.

Isotopes Edit

Like every other element heavier than lead, vanthoffium has no stable isotopes. The longest-lived isotope is 440Vh with a half-life of only 4.6 milliseconds. It undergoes spontaneous fission, splitting into two or three lighter nuclei plus neutrons like the examples.

Vh → 261
No + 127
I + 52 1
Vh → 197
Au + 132
Xe + 48
Ti + 63 1

Every vanthoffium meta states have half-lives shorter than the longest-lived ground state isotope 440Vh, which is unusual for elements heavier than arrhenium. 443m2Vh has half-life is 2.7 milliseconds. The second longest half-life is 370 microseconds, for 442mVh.

Chemical properties and compounds Edit

Vanthoffium is very unreactive due to its unexpectedly small atomic size caused by high charge density between so many protons and electrons. The most stable oxidation state is +1 (monovalent), and can donate no more than three electrons. Hence this, Vh+ ions is most stable in aqueous solutions, coloring light orange in water but dark red in acetylene. Vanthoffium has the highest ionization energy of any scandium family elements at 9.9 eV. The second highest ionization energy is scandium, 6.6 eV. In response, vanthoffium has the highest electronegativity with the second highest is again scandium.

There are examples of vanthoffium compounds despite its noble feature of the element. Vanthoffium(III) nitride (VhN) is a peach crystalline solid. Vanthoffium(V) oxide (Vh2O5) is a red powder. Vanthoffium trinitrate (Vh(NO3)3) is colored green as a powder or in solution. Vanthoffium(V) chloride (VhCl5) is a blue ionic solid obtained by reacting either with hydrochloric acid or chlorine gas. Vanthoffium(I) cyanide (VhCN) is a volatile white powder and vanthoffium sulfate (VhSO4) is a pale yellow powder. Vanthoffium can also form compounds in the +0 state, such as Vh(SN)2 and Vh(CO)5.

Occurrence Edit

It is almost certain that vanthoffium 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. Vanthoffium has an estimated abundance of 5 × 10−33 by mass, which amounts to 1.68 × 1020 kilograms.

Synthesis Edit

To synthesize most stable isotopes of vanthoffium, 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 immediately undergo fission. Here's couple of example equations in the synthesis of the most stable isotope, 440Vh.

Pb + 181
Ta + 51 1
n → 440
Db + 120
Sn + 48 1
n → 440
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