|Name in Saurian|| Ujkedaim (Ud)|
|Systematic name|| Untriennium (Ute)|
|Location on the periodic table|
|Previous element||Chadwickium (138Ch)|
|Next element||Edisonium (140Ed)|
|Atomic mass||383.1759 u, 636.2785 yg|
|Atomic radius||142 pm, 1.42 Å|
|Van der Waals radius||166 pm, 1.66 Å|
|Nucleons||380 (139 p+, 241 n0)|
|Nuclear radius||8.66 fm|
|Electron configuration|| [Mc] 5g13 6f2 7d2 8p1/2 8s2|
2, 8, 18, 32, 45, 20, 10, 4
|Oxidation states|| +3, +4, +5|
(mildly basic oxide)
|First ionization energy||665.2 kJ/mol, 6.895 eV|
|Electron affinity||108.3 kJ/mol, 1.122 eV|
|Covalent radius||164 pm, 1.64 Å|
|Molar mass||383.176 g/mol|
|Molar volume||55.242 cm3/mol|
|Atomic number density||1.09 × 1022 cm−3|
|Average atomic separation||451 pm, 4.51 Å|
|Speed of sound||4419 m/s|
|Crystal structure||Simple tetragonal|
|Melting point|| 826.51 K, 553.36°C|
|Boiling point|| 1475.66 K, 1202.51°C|
|Liquid range||649.15 K/°C, 1168.46°F/°R|
|Triple point|| 826.48 K, 553.33°C|
@ 7.1855 μPa, 5.3896 × 10−8 torr
|Critical point|| 2651.12 K, 2377.97°C|
@ 41.1465 MPa, 406.085 atm
|Heat of fusion||8.013 kJ/mol|
|Heat of vaporization||150.529 kJ/mol|
|Heat capacity|| 0.05522 J/g/K, 0.09939 J/g/°R|
21.159 J/mol/K, 38.086 J/mol/°R
|Universe (by mass)|| Relative: 2.52 × 10−36|
Absolute: 8.45 × 1016 kg
Astonium is the fabricated name of a hypothetical element with the symbol An and atomic number 139. Astonium was named in honor of Francis William Aston (1877–1945), who discovered isotopes and formulate the whole number rule of atomic masses. This element is known in scientific literature as untriennium (Ute), or simply element 139. Astonium is the nineteenth element of the lavoiside series and located in periodic table coordinate 5g19.
Astonium is a brownish gray metal that shows golden luster whose density is approaching 7 g/cm3, similar to zinc's. The crystals form tetragonal in the solid state at room temperature (25°C, 77°F), but transitions to face-centered cubic at 272°C (522°F). At room temperature, the atoms are separated by 4.51 Å (451 pm) on average. Heating the metal causes atoms to move further apart while cooling it causes atoms to move closer to each other.
Astonium melts at 553°C (1028°F) and boils at 1203°C (2197°F), corresponding to its liquid range of 649°C (1168°F). It requires one and a half dozen times more energy to boil this element than melting. Its triple point pressure is 7 micropascals, where all three phases of matter are equally stable in equilibrium at temperature few hundredth of a degree lower than its melting point.
The atom contains 24 orbitals in 8 shells where 139 electrons reside. Its electronegativity, the ability to acquire electrons from other atoms, is 1.33. Its atomic radius is 142 pm, similar to silver (144 pm). The nucleus contains 139 protons and 241 neutrons, adding these two would have a mass number 380 and dividing neutrons by protons would yield a nuclear ratio of 1.73. The mass of the nucleus is not exactly 380 daltons, but 383.10 daltons, because each nucleons have masses slightly over one dalton by less than 1%. However when taking electrons into account, the total mass of the atom is 383.18 daltons, which is just 0.02% greater than the mass of its nucleus.
Like every other elements heavier than lead, astonium has no stable isotopes. The most stable isotope is 380An with a brief half-life of 14 milliseconds. It undergoes spontaneous fission, splitting into two lighter nuclei as well as neutrons like the following example.
Astonium has meta states with much longer half-lives than ground state isotopes, including 381m1An (t½ = 5.1 min), 381m2An (t½ = 58.7 sec), 377mAn (t½ = 19.7 sec), and 375mAn (t½ = 3.8 sec).
Astonium is not very chemically active based on its electronegativity of 1.53 and first ionization energy 6.9 eV. It can slowly react with strong acids such as sulfuric acid and hydrochloric acid to form An(SO4)2 and AnCl4, respectively. Astonium does not readily combine with oxygen from the air, but it tarnishes at moderate rate when the metal is heated to around the boiling point of water. In addition to a +4 oxidation state in compounds just mentioned, the element also takes on a +3 and +5 states. Astonium forms aqueous solution with An4+ (yellow-green) or An5+ (hot pink).
Astonium can form complex anions such as AnO2−
4 and AnPS−
Astonium(III) boride (AnB) is a refractive binary compound between astonium and boron. Astonium can form trihalides or pentahalides, such as AnF5, AnCl5, AnBr3, and AnI5. Astonium can form oxides when metal exposes to the oxygen-rich air for a while, it can either form An2O3 or An2O5, both are black powder or as brittle form covering the original shape of metal that can easily be scraped off. It can also form a nitride, An3N4, as well as sulfide, AnS2, when combined together would result in An(SN)4 and astonium metal.
- An3N4 + 2 AnS2 → An(SN)4 + 4 An
The examples of organoastonium compounds are diphenylastonium (Ph2An) and astonium fructose (C6H8O6An).
Occurrence and synthesis Edit
It is almost certain that astonium 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 astonium 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 astonium in the universe by mass is 2.52 × 10−36, which amounts to 8.45 × 1016 kilograms.
To go along with other such civilizations, humans on Earth may eventually have the capability to synthesize astonium. To synthesize most stable isotopes of astonium, 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 380An.