|Name in Saurian|| Sulodtajxaim (Sl)|
|Systematic name|| Untrihexium (Uth)|
|Location on the periodic table|
|Previous element||Meyerium (135My)|
|Next element||Feynmanium (137Fy)|
|Atomic mass||376.1178 u, 624.5582 yg|
|Atomic radius||152 pm, 1.52 Å)|
|Van der Waals radius||174 pm, 1.74 Å|
|Nucleons||373 (136 p+, 237 n0)|
|Nuclear radius||8.60 fm|
|Electron configuration|| [Mc] 5g10 6f4 8s2 8p2|
2, 8, 18, 32, 42, 22, 8, 4
|Oxidation states|| +4, +6|
(mildly basic oxide)
|First ionization energy||600.1 kJ/mol, 6.220 eV|
|Electron affinity||192.5 kJ/mol, 1.995 eV|
|Covalent radius||171 pm, 1.71 Å|
|Molar mass||376.118 g/mol|
|Molar volume||63.813 cm3/mol|
|Atomic number density||9.44 × 1021 cm−3|
|Average atomic separation||473 pm, 4.73 Å|
|Speed of sound||2873 m/s|
|Crystal structure||Simple hexagonal|
|Color||Dark turquoish gray|
|Melting point|| 801.98 K, 528.83°C|
|Boiling point|| 1897.68 K, 1624.53°C|
|Liquid range||1095.70 K/°C, 1972.25°F/°R|
|Triple point|| 801.97 K, 528.82°C|
@ 230.75 mPa, 1.7308 × 10−4 torr
|Critical point|| 3412.22 K, 3139.07°C|
@ 14.1969 MPa, 140.113 atm
|Heat of fusion||7.749 kJ/mol|
|Heat of vaporization||171.561 kJ/mol|
|Heat capacity|| 0.05644 J/g/K, 0.10159 J/g/°R|
21.228 J/mol/K, 38.211 J/mol/°R
|Universe (by mass)|| Relative: 7.83 × 10−30|
Absolute: 2.62 × 1023 kg
Cavendishium is the fabricated name of a theoretical element with the symbol Cv and atomic number 136. Cavendishium was named in honor of Henri Cavendish (1731–1810), who discovered some of the most important elements in the periodic table such as hydrogen and nitrogen. This element is known in scientific literature as untrihexium (Uth), or simply element 136. Cavendishium is the sixteenth element of the lavoiside series and located in periodic table coordinate 5g16.
Cavendishium is a dark turquoish gray metal whose density is 5.89 g/cm3 and molar volume 63.8 cm3/mol. The crystals form hexagonals and the average atomic separation is 473 pm. In one cubic centimeter of metal, there are nearly 9½ sextillion cavendishium atoms, which is actually quite few compared to other metals. The number of atoms is computed from average atomic separation and its bulk density.
Cavendishium's melting point is 802 K (529°C). If we multiply its melting point in Kelvin by its liquid ratio of 2.37, we get the boiling point, which is 1898 K (1625°C). Its heat of fusion (7.75 kJ/mol) and heat of vaporization (171.6 kJ/mol) are related to melting and boiling points in Kelvin, respectively. The molar heat capacity is 21.23 J/mol/K.
Cavendishium contains 136 electrons, identical to the number of protons in its nucleus, making this atom neutral. In the electron cloud, it has 23 orbitals in 8 shells, together with the number of electrons would result in the electron notation of 136-8-23.
Cavendishium atom masses 376 amu, with 99.98% of the mass make up the nucleus that makes up only a tiny portion of its atomic size. Its atomic radius is 152 pm while its nuclear radius is 0.00860 pm, that's a quotient of 18000. Which means that the whole atom takes up 5.5 trillion times more space than its nucleus!
Like every other elements heavier than lead, cavendishium has no stable isotopes. The most stable isotope is 373Cv with a half-life of 4.5 days, alpha decaying to 369Ah. All other isotopes have half-lives less than 4.1 hours (372Cv) and majority of these have half-lives less than 2.8 minutes. The most stable meta state is 370m2Cv with a half-life of 2 minutes 21 seconds, while 370m1Cv lasts a bit shorter at 1 minute 37 seconds.
Cavendishium is quite electropositive meaning it readily reacts with electronegative elements such as oxygen (for example by air), fluorine, and chlorine. Due to its basic nature of cavendishium, it neutralizes acids by displacing hydrogen atoms. The metal also displaces hydrogen atoms in water to form a basic solution of cavendishium hydroxide. When dissolved in water, green Cv6+ ions is more common than blue Cv4+.
Cavendishium hexafluoride (CvF6) is a yellow crystalline solid while cavendishium tetrafluoride (CvF4) is also a yellow crystalline solid. They both hydrolyse in water respectively to CvOF4 and CvOF2 (both white solids) by liberating hydrogen gas. When exposed to air, it quickly form cavendishium dioxide (CvO2), which is black amorphous oxide. Further oxidation produces cavendishium trioxide (CvO3), a purplish black amorphous solid. Another halide in addition to fluoride is chloride: CvCl4 and CvCl6, both white ionic solids. Another cavendishium chalcide in addition to oxide are CvS2 and CvS3. There are also heavier chalcides, CvSe2, CvTe2, and CvPo2.
Occurrence and synthesis Edit
It is certain that cavendishium is virtually nonexistent on Earth, and is extremely rare in the universe. Since every element heavier than lithium were produced by stars, then cavendishium must be produced in stars, and then thrown out into space by exploding stars. But it is virtually 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 can only practically be made by advanced technological civilizations. An estimated abundance of cavendishium in the universe by mass is 7.83 × 10−30, which amounts to 2.62 × 1023 kilograms or about 40% the mass of Mars worth of cavendishium.
To go along with other such civilizations, humans on Earth may eventually have the capability to synthesize cavendishium. To synthesize most stable isotopes of cavendishium, 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. Here's couple of example equations in the production of the most stable isotope 373Cv.