|Name in Saurian|| Umfohaim (Uf)|
|Systematic name|| Unpentoctium (Upo)|
|Location on the periodic table|
|Above element||Seaborgium (106Sg)|
|Previous element||Kelvinium (157Ke)|
|Next element||Vanderwaalsium (159Vw)|
|Atomic mass||453.7665 u, 753.4970 yg|
|Atomic radius||113 pm, 1.13 Å|
|Van der Waals radius||176 pm, 1.76 Å|
|Nucleons||450 (158 p+, 292 n0)|
|Nuclear radius||9.16 fm|
|Electron configuration|| [Mc] 5g18 6f14 7d4 8s2 8p2|
2, 8, 18, 32, 50, 32, 12, 4
|Oxidation states|| 0, +2, +4, +6, +8|
(weakly acidic oxide)
|First ionization energy||516.6 kJ/mol, 5.354 eV|
|Electron affinity||64.0 kJ/mol, 0.663 eV|
|Covalent radius||139 pm, 1.39 Å|
|Molar mass||453.767 g/mol|
|Molar volume||15.285 cm3/mol|
|Atomic number density||3.94 × 1022 cm−3|
|Average atomic separation||294 pm, 2.94 Å|
|Speed of sound||4602 m/s|
|Crystal structure||Body centered cubic|
|Melting point|| 799.13 K, 525.98°C|
|Boiling point|| 1051.72 K, 778.57°C|
|Liquid range||252.59 K/°C, 454.66°F/°R|
|Triple point|| 798.96 K, 525.81°C|
@ 683.16 Pa, 5.1242 torr
|Critical point|| 3560.44 K, 3287.29°C|
@ 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
|Universe (by mass)|| Relative: 4.77 × 10−36|
Absolute: 1.60 × 1017 kg
Amperium is the fabricated name of a hypothetical 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 scientific literature as unpentoctium (Upo), dvi-tungsten, or simply element 158. Amperium is the heaviest member of the chromium family (below chromium, molybdenum, tungsten, and seaborgium) and is the fourth member of the vanthoffide series; this element is located in periodic table coordinate 7d4.
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 splitting 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 phase points and very narrow liquid range for a metal due to completely closed electron configurations including filled 7d3/2 and 8p1/2 subshells. The temperature at which solid amperium becomes a liquid is 526°C and the maximum temperature where liquid amperium can exist at atmospheric pressure is 779°C, corresponding to its liquid ratio of 1.32. 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.
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 in nucleus. The distance between center of nucleus and outermost electron shell is 113 picometers with the real radius of 133 picometers. Nucleus is very small compared to its atomic size, the radius is about 9.2 femtometers, which is about 1⁄12000 the size of the atom.
Like every other elements heavier than lead, amperium has no stable isotopes. The most stable isotope is 450Ap with a half-life (t½) of 35 minutes, which is unusually long for elements in this region of the periodic table. Like all other elements in this region, it undergoes spontaneous fission, splitting into two or three lighter nuclei plus neutrons like the following examples.
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.
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), different from +6 for lighter cogeners tungsten and seaborgium. 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−
6) and hexachloroamperate (ApCl2−
6). Ap4+ is blue in most aqueous solutions. The 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.
Occurrence and synthesis Edit
It is almost certain that amperium doesn't exist on Earth at all, but it is believed to exist somewhere in the universe, at least in very tiny amounts. Since every element heavier than lithium were produced by stars, then amperium 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 heavy element. Instead, this element virtually can only be made by advanced technological civilizations. An estimated abundance of amperium in the universe by mass is 4.77 × 10−36, which amounts to 1.60 × 1017 kilograms or the mass of Saturn's moon Promethius worth of this element.
To go along with other such civilizations, humans on Earth may eventually have the capability to synthesize amperium. 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 extremely difficult since it requires vast amounts 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 450Ap.