Symbol Du
Atomic number 143
Pronunciation /'düm•äs•ē•(y)üm/
Named after Jean-Baptiste Dumas
Name in Saurian Timujaim (Ti)
Systematic name Unquadtrium (Uqt)
Location on the periodic table
Period 8
Family Lanthanum family
Series Dumaside series
Coordinate 6f1
Element above Dumasium Actinium
Element left of Dumasium Butlerovium
Element right of Dumasium Scheelium
Atomic properties
Subatomic particles 534
Atomic mass 394.2679 u, 654.6972 yg
Atomic radius 145 pm, 1.45 Å
Covalent radius 157 pm, 1.57 Å
van der Waals radius 189 pm, 1.89 Å
Nuclear properties
Nucleons 391 (143 p+, 248 no)
Nuclear ratio 1.73
Nuclear radius 8.74 fm
Half-life 26.244 μs
Decay mode Spontaneous fission
Decay product Various
Electronic properties
Electron notation 143-8-24
Electron configuration [Og] 5g17 6f2 7d2 8s2 8p2
Electrons per shell 2, 8, 18, 32, 49, 20, 10, 4
Oxidation states +1, +2, +3, +4, +6, +8
(a mildly basic oxide)
Electronegativity 1.78
First ionization energy 739.0 kJ/mol, 7.659 eV
Electron affinity 87.0 kJ/mol, 0.902 eV
Physical properties
Bulk properties
Molar mass 394.268 g/mol
Molar volume 51.998 cm3/mol
Density 7.582 g/cm3
Atomic number density 1.53 × 1021 g−1
1.16 × 1022 cm−3
Average atomic separation 442 pm, 4.42 Å
Speed of sound 2869 m/s
Magnetic ordering Paramagnetic
Crystal structure Face-centered cubic
Color Gray
Phase Solid
Thermal properties
Melting point 655.59 K, 1180.07°R
382.44°C, 720.40°F
Boiling point 2904.24 K, 5227.64°R
2631.09°C, 4767.97°F
Liquid range 2248.65 K, 4047.57°R
Liquid ratio 4.43
Triple point 655.34 K, 1179.62°R
382.19°C, 719.95°F
@ 78.914 fPa, 5.9191 × 10−16 torr
Critical point 5322.62 K, 9580.71°R
5049.47°C, 9121.04°F
@ 21.2552 MPa, 209.774 atm
Heat of fusion 6.950 kJ/mol
Heat of vaporization 275.565 kJ/mol
Heat capacity 0.05062 J/(g•K), 0.09112 J/(g•°R)
19.959 J/(mol•K), 35.926 J/(mol•°R)
Abundance in the universe
By mass Relative: 2.33 × 10−33
Absolute: 7.82 × 1019 kg
By atom 1.55 × 10−34

Dumasium is the provisional non-systematic name of a theoretical element with the symbol Du and atomic number 143. Dumasium was named in honor of Jean-Baptiste Dumas (1800–1884), who determined atomic weights and molecular weights. This element is known in the scientific literature as unquadtrium (Uqt), eka-actinium, or simply element 143. Dumasium is the first member of the dumaside series, found in the third row of f-block (below lanthanum and actinium); this element is located in the periodic table coordinate 6f1.

Atomic properties Edit

Dumasium has the mass number 391, 248 more than its atomic number, corresponding that there are 248 neutrons, and 143 protons that make up the nucleus. Despite it is the third element of the f-block series, there are only two electrons in the f-orbital and didn't add it prior to this element, and the g-orbital needs one more electron to complete its orbital (17/18).

Dumasium has the atomic radius of 155 picometers, identical in value to lithium and masses 394.3 daltons, twice as heavy as gold atom.

Isotopes Edit

Like every other element heavier than lead, dumasium has no stable isotopes. The longest-lived isotope is 391Du with a very brief half-life (t½) of 26 microseconds. It undergoes spontaneous fission, splitting into two lighter nuclei plus neutrons like the example.

Du → 202
Hg + 153
I + 36 1

The most stable dumasium isomer is 388m2Du with a half-life of 417 milliseconds, 16,000 times longer than the most stable ground-state isotope. 388m2Du decays either by isomeric transition or fission.

Chemical properties and compounds Edit

Based on the element's location on the periodic table, dumasium should have similar chemical properties to the above element actinium. The oxidation states include the most common +6 and +8, compared to +5 for actinium, and has the electronegativity of 1.78, compared to 1.48 for actinium. So this makes dumasium less reactive than its lighter homologue. So unlike actinium, it does not corrode when exposed to air even if oxygen is plentiful. It is insoluble in water but slightly soluble in carbon disulfide and mineral acids.

Dumasium reacts most readily with free halogens to form very colorful ionic halides, such as fluorine to form DuF3 or DuF4 (red and orange respectively), chlorine to form DuCl3 or DuCl4 (blue and green respectively), bromine to form DuBr3 or DuBr4 (purple and lavendar respectively), iodine to form DuI2 or DuI3 (light brown and peach respectively). At higher temperatures, it can combine with astatine to form DuAt2 or DuAt3 (yellow and greenish brown respectively), tennessine to form DuTn or DuTn2 (black and gray respectively), and bunsenine to form DuBs or DuBs2 (dun and slight brown-tinted black respectively). Dumasium tarnishes in the air to form DuO3 (light gray) or DuO4 (gray) and with nitrogen at high temperatures to form DuN (dark gray) or DuN2 (black).

Physical properties Edit

Like many metals, dumasium is gray that shows only a dull luster. Its molar mass is 394 g/mol while its molar volume is 52.5 cm3/mol, corresponding to its density of 7.58 g/cm3. The speed of sound through the thin rod of metal is 2869 m/s, which is slower than through an average element.

Its liquid state ranges from 656 K to 2904 K, quotient between these values would provide a relatively high liquid ratio of 4.43, meaning its boiling point is 4.43 times hotter than its melting point. However it requires 40 times more energy to boil it than to melt it.

Occurrence Edit

It is almost certain that dumasium 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 dumasium in the universe by mass is 2.33 × 10−33, which amounts to 7.82 × 1019 kilograms.

Synthesis Edit

To synthesize most stable isotopes of dumasium, 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 quickly undergo fission. Here's couple of example equations in the synthesis of the most stable isotope, 391Du.

Pb + 145
Pm + 38 1
n → 391
Mt + 80
Se + 24 1
n → 391
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