Symbol Av
Atomic number 149
Pronunciation /'av•ō•ga•drē•(y)üm/
Named after Amedeo Avogadro
Name in Saurian Ulewuthaim (Ul)
Systematic name Unquadennium (Uqe)
Location on the periodic table
Period 8
Family Europium family
Series Dumaside series
Coordinate 6f7
Element above Avogadrium Americium
Element left of Avogadrium Faradium
Element right of Avogadrium Schrodium
Atomic properties
Subatomic particles 562
Atomic mass 416.4535 u, 691.5372 yg
Atomic radius 127 pm, 1.27 Å
Covalent radius 142 pm, 1.42 Å
van der Waals radius 173 pm, 1.73 Å
Nuclear properties
Nucleons 413 (149 p+, 264 no)
Nuclear ratio 1.77
Nuclear radius 8.90 fm
Half-life 41.793 ns
Decay mode Spontaneous fission
Decay product Various
Electronic properties
Electron notation 149-8-24
Electron configuration [Og] 5g18 6f6 7d3 8s2 8p2
Electrons per shell 2, 8, 18, 32, 50, 24, 11, 4
Oxidation states +1, +2, +3, +4, +5, +6, +7, +8, +10
(a weakly basic oxide)
Electronegativity 2.07
First ionization energy 868.0 kJ/mol, 8.996 eV
Electron affinity 71.6 kJ/mol, 0.742 eV
Physical properties
Bulk properties
Molar mass 416.453 g/mol
Molar volume 28.090 cm3/mol
Density 14.825 g/cm3
Atomic number density 1.45 × 1021 g−1
2.14 × 1022 cm−3
Average atomic separation 360 pm, 3.60 Å
Speed of sound 5059 m/s
Magnetic ordering Paramagnetic
Crystal structure Face-centered cubic
Color Yellow
Phase Solid
Thermal properties
Melting point 688.25 K, 1238.85°R
415.10°C, 679.18°F
Boiling point 4700.20 K, 8460.36°R
4427.05°C, 8000.69°F
Liquid range 4011.95 K, 7321.51°R
Liquid ratio 6.83
Triple point 688.15 K, 1238.67°R
415.00°C, 679.00°F
@ 8.4910 × 10−14 aPa, 6.3688 × 10−34 torr
Critical point 14006.59 K, 25211.86°R
13733.44°C, 24752.19°F
@ 178.9003 MPa, 1765.614 atm
Heat of fusion 6.160 kJ/mol
Heat of vaporization 432.598 kJ/mol
Heat capacity 0.05738 J/(g•K), 0.10328 J/(g•°R)
23.895 J/(mol•K), 43.011 J/(mol•°R)
Abundance in the universe
By mass Relative: 9.54 × 10−35
Absolute: 3.20 × 1018 kg
By atom 6.02 × 10−36

Avogadrium is the provisional non-systematic name of a theoretical element with the symbol Av and atomic number 149. Avogadrium was named in honor of Amedeo Avogadro (1776–1856), who developed the molecular theory, determined the number of particles in one mole of substance (known as Avogadro constant), and contributed gas law. This element is known in the scientific literature as unquadennium (Uqe), eka-americium, or simply element 149. Avogadrium is the seventh member of the dumaside series, found in the third row of f-block (below europium and americium); this element is located in the periodic table coordinate 6f7.

Atomic properties Edit

Avogadrium atom masses 416.45 daltons and sizes 152 pm in radius. It has 562 component particles, 73% of all components lie in a region only approximately 114000 the radius of the atom, which is the atomic nucleus with the same value of charge as its atomic number. Outside the nucleus, the electron notation is 149-8-24, meaning there are 149 electrons in 8 shells and 24 orbitals.

Isotopes Edit

Like every other element heavier than lead, avogadrium has no stable isotopes. The longest-lived isotope is 413Av with a fission half-life of 4145 nanoseconds. Fission means splitting into two or three lighter nuclei plus neutrons like the example.

Av → 192
Os + 181
Ta + 40 1
Av → 209
Bi + 130
Te + 28
Si + 46 1

Like every element heavier than calcium, avogadrium has metastable isomers. The longest lived isomer is 413m1Av with a half-life of 5.6 milliseconds.

Chemical properties and compounds Edit

Because of the smearing out the orbitals with filled g-orbital and partially filled f-orbital, avogadrium is an unreactive element, meaning it does not display eka-americium properties despite the relative locations on the periodic table. As a result, avogadrium is corrosion-resistent, either in air, water, or acids, though slightly soluble in acids. The element commonly displays a +6 and +8 oxidation state unlike americium, as well as +10 and number less than +6. Av6+ is the only stable ion in aqueous solutions. This ion forms purple solution in hydrochloric acid, but crimson in carbonic acid.

Despite its unreactivity, avogadrium has several notable compounds as well as organoavogadrium compounds. Avogadrium hexafluoride (AvF6) and octafluoride (AvF8) are both white ionic salts appearing like sodium chloride (NaCl). AvCl6 is a sky blue ionic or crystalline salt while AvCl8 is white. If we put avogadrium in the flame for a few minutes, it first melts to a thick yellow liquid quickly and then tarnishes and solidifies to a brittle brown oxide AvO3, which with further exposure to the flame darkens this substance even more as it oxidizes to AvO4, which is brownish black and crumbly.

Other than oxides and halides, there are other avogadrium compounds of note. AvS3 is a red powder that is soluble in water. Av(SiO2)2 is a gray crystalline solid. Av(PF3)4 is a white crystalline solid that dephosphorizes in salt water to give AvF3, phosphoric acid (H3PO4), PF3, and few other products.

Av(PF3)4 + 6 H2O + 2 NaCl → AvF3 + H3PO4 + 3 PF3 + 2 NaOH + 2 HCl + 2.5 H2

Organoavogadrium compounds include AvHCO2 (avogadrium formate), AvCH3CO2 (avogadrium acetate), and AvCH3 (methylavogadrium or avogadrium methanide).

Physical properties Edit

Avogadrium is a bright, vivid yellow metal that is malleable and ductile. Avogadrium(III) ions fluorescences in brilliant red light at 636 nm. The molar mass is 41649 g/mol while its molar volume is 28111 cm3/mol; dividing molar mass and volume yields a density of 1456 g/cm3. Its speed of sound is 5059 m/s and its lattice is in the form of face-centered cubic.

Avogadrium has the widest liquid range of any element. Liquid avogadrium ranges from 1239°R (779°F) (melting point) to roughly 8460°R (8001°F) (boiling point). It has the second widest liquid range (7322°R) and the third highest liquid ratio (6.83) of any element. A reason why the liquid range and quotient is so wide is because of an exceptionally low vapor pressure despite its low melting point, due to strong metallic bonding of liquid metal. Due to this, the amount of energy needed to convert from liquid to gas during boiling (called heat of vaporization) is merely 70 times greater than energy needed to convert from solid to liquid during melting (called heat of fusion), which is 3½ times the average ratio of 20. Its triple point, a point on the phase diagram where solid, liquid, and gas coexist in equilibrium, is at a temperature 0.18°R lower than its melting point but at near-zero pressure of 8.49 × 10−32 Pa.

Occurrence Edit

It is almost certain that avogadrium 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 avogadrium in the universe by mass is 9.54 × 10−35, which amounts to 3.20 × 1018 kilograms.

Synthesis Edit

To synthesize most stable isotopes of avogadrium, 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, 413Av.

Rn + 152
Eu + 39 1
n → 413
Sg + 98
Tc + 39 1
n → 413
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