Symbol Ap
Atomic number 158
Pronunciation /'am•pēr•ē•(y)üm/
Named after André-Marie Ampère
Name in Saurian Umfohaim (Uf)
Systematic name Unpentoctium (Upo)
Location on the periodic table
Group 4
Period 8
Family Titanium family
Series Kelvinide series
Coordinate 7d2
Element above Amperium Rutherfordium
Element left of Amperium Kelvinum
Element right of Amperium Vanderwaalsium
Atomic properties
Subatomic particles 608
Atomic mass 453.7665 u, 753.4970 yg
Atomic radius 113 pm, 1.13 Å
Covalent radius 139 pm, 1.39 Å
van der Waals radius 176 pm, 1.76 Å
Nuclear properties
Nucleons 450 (158 p+, 292 no)
Nuclear ratio 1.85
Nuclear radius 9.16 fm
Half-life 98.650 s
Decay mode Spontaneous fission
Decay product Various
Electronic properties
Electron notation 158-8-24
Electron configuration [Og] 5g18 6f14 7d4 8s2 8p2
Electrons per shell 2, 8, 18, 32, 50, 32, 12, 4
Oxidation states 0, +2, +4, +6, +8
(a weakly acidic oxide)
Electronegativity 1.53
First ionization energy 516.6 kJ/mol, 5.354 eV
Electron affinity 64.0 kJ/mol, 0.663 eV
Physical properties
Bulk properties
Molar mass 453.767 g/mol
Molar volume 15.285 cm3/mol
Density 29.687 g/cm3
Atomic number density 1.33 × 1021 g−1
3.94 × 1022 cm−3
Average atomic separation 294 pm, 2.94 Å
Speed of sound 4602 m/s
Magnetic ordering Paramagnetic
Crystal structure Body-centered cubic
Color Red
Phase Solid
Thermal properties
Melting point 799.13 K, 1438.43°R
525.98°C, 978.76°F
Boiling point 1051.72 K, 1893.09°R
778.57°C, 1433.42°F
Liquid range 252.59 K, 454.66°R
Liquid ratio 1.32
Triple point 798.96 K, 1438.12°R
525.81°C, 978.45°F
@ 683.16 Pa, 5.1242 torr
Critical point 3560.44 K, 6408.79°R
3287.29°C, 5949.12°F
@ 4746.3153 MPa, 46842.638 atm
Heat of fusion 7.308 kJ/mol
Heat of vaporization 129.513 kJ/mol
Heat capacity 0.05488 J/(g•K), 0.09878 J/(g•°R)
24.902 J/(mol•K), 44.823 J/(mol•°R)
Abundance in the universe
By mass Relative: 4.77 × 10−31
Absolute: 1.60 × 1022 kg
By atom 2.76 × 10−32

Amperium is the provisional non-systematic name of a theoretical element with the symbol Ap and atomic number 158. Amperium was named in honor of André-Marie Ampère (1775–1836), who pioneered electrodynamics. This element is known in the scientific literature as unpentoctium (Upo), dvi-hafnium, or simply element 158. Amperium is the heaviest member of the titanium family (below titanium, zirconium, hafnium, and rutherfordium) and is the second member of the kelvinide series; this element is located in the periodic table coordinate 7d2.

Atomic properties Edit

Amperium atom contains 450 nucleons that make up the nucleus. There are two types of nucleons: protons and neutrons. Protons carry positive charge and neutrons carry no charge. There are 158 protons, hence its atomic number, and 292 neutrons, corresponding to the nuclear ratio of 1.85, meaning there are less than two neutrons per proton. Since there are 158 positively charge particles in the nucleus, nucleus has a charge of +158. However, the atom has no overall charge, which doesn't make sense, unless if there are equal number of negatively charged particles in locations other than nucleus. The negatively charge particles are electrons, which are found in the cloud of orbitals and shells surrounding the nucleus much like planetary systems. Since it is the fourth element of the d-block series, there are four electrons occupying in the d-orbital. The atom contains 608 component particles, with 74% of these are nucleons.

The atom masses 454 daltons, with 99.98% of its mass are located in the nucleus. The distance between center of nucleus and outermost electron shell is 113 picometers, while the real radius (van der Waals radius) is 133 picometers. Nucleus is very small compared to its atomic size, the radius is about 9.2 femtometers, which is about 112000 the size of the atom.

Isotopes Edit

Like every other element heavier than lead, amperium has no stable isotopes. The longest-lived isotope is 450Ap with a half-life (t½) of 98⅔ seconds. Like all other elements in this region, it undergoes spontaneous fission, splitting into two or three lighter nuclei plus neutrons like the examples.

Ap → 293
Nh + 103
Rh + 54 1
Ap → 247
Cm + 2 69
Ga + 65 1

Other amperium isotopes include 449Ap (t½ = 27 min), 453Ap (t½ = 3.1 min), 455Ap (t½ = 31 sec), and 446Ap (t½ = 5.8 sec). Amperium can form excited states of isotopes, including 452mAp (t½ = 157 days), 448mAp (t½ = 4.7 hrs), 446mAp (t½ = 21 min), and 445mAp (t½ = 71 sec). All these meta states undergo spontaneous fission like ground state isotopes.

Chemical properties and compounds Edit

Due to 7d orbital containing four electrons to achieve full 7d3/2 split orbital, the atom restrained itself from exchanging electrons. As a result, amperium is a noble metal meaning it is unreactive. But the most common oxidation state is +4 (tetravalent), same as lighter cogeners hafnium and rutherfordium. For lighter cogeners, they give up all two s-electrons in addition to four d-electrons, but for amperium, it doesn't give up s-electrons due to bound state of 8s orbital because of the relativistic effects. If amperium forms +6 state (hexavalent), it gives up 8p1/2 electrons instead.

Amperium forms anionic complexes such as hexafluoroamperate (ApF2−
) and hexachloroamperate (ApCl2−
). Ap4+ is blue in most aqueous solutions. Examples of exceptions are green in silicic acid, orange in copper sulfate, purple in stannic acid and calcium nitrate.

ApO2 (amperium(IV) oxide) is an indigo powder. Amperium carbide (ApC) is a refractory compound with a melting point of 2968°C (5374°F) while amperium rutherfordium carbide (Ap6Rf2C8) has the melting point of 3608°C (6526°F) and superconducting below −25°C. Amperium also forms halides, such as ApF4 and ApCl4, which hydrolyse to ApOF2 and ApOCl2, respectively. Amperium salts include Ap(CO3)2, Ap(NO3)3, Ap(PF3)4, and Ap(SiO3)2.

ApC can react with water or hydrocarbons to form organoamperium compounds.

Physical properties Edit

As it is common for period 8 elements, amperium is not gray nor white, instead, amperium is a dense, brick red shiny metal. The metal is red due to electrons oscillating between the orbitals in energies corresponding to the red region of the electromagnetic spectrum, which is the same reason why gold is yellow. It has a density of 30 g/cm3, 1⅓ times denser than the densest known naturally occurring element osmium. It has a body-centered cubic crystal structure, but transforming into simple cubic at 1088°C. The average distance between amperium atoms is about three angstroms and the sound travels through the bulk at over 4600 meters per second.

Amperium is paramagnetic, however it doesn't display this property at all temperatures because magnetism can be disrupted by a certain degree of vibrations between atoms. This metal becomes antiferromagnetic when cooled to below its Néel point of −38°C, meaning it is repelled by magnetic field. For comparison, chromium, which is a lighter family member of amperium, is antiferromagnetic below its Néel point of 35°C.

Like most metals, amperium is solid at room temperature, but it has a very low melting and boiling points and very narrow liquid range for a metal due to completely closed electron configurations including filled 7d3/2 and 8p1/2 subshells. This is in stark contrast with above elements hafnium and rutherfordium, which each have very high melting and boiling points. The temperature at which solid amperium becomes a liquid is 526°C and the maximum temperature where liquid amperium can exist at Earth's atmospheric pressure is 779°C, corresponding to its liquid ratio of 1.32, slightly lower than water (1.35). Heat of fusion, amount of energy needed to melt one mole of this element, is 7.3 kilojoules; heat of vaporization, same definition as heat of fusion but applies to boiling, is 129.5 kilojoules.

Occurrence Edit

It is almost certain that amperium 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 amperium in the universe by mass is 4.77 × 10−31, which amounts to 1.60 × 1022 kilograms or about 1.2 times more abundant in mass of this element than the total mass of Pluto itself.

Synthesis Edit

To synthesize most stable isotopes of amperium, 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, 450Ap.

Cm + 152
Sm + 51 1
n → 450
Nh + 103
Rh + 54 1
n → 450
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