2007 Schools Wikipedia Selection. Related subjects: Chemical elements

115 ununquadiumununpentiumununhexium


Periodic Table - Extended Periodic Table
Name, Symbol, Number ununpentium, Uup, 115
Chemical series presumably poor metals
Group, Period, Block 15, 7, p
Appearance unknown, probably silvery
white or metallic grey
Atomic mass (299) g/mol
Electron configuration perhaps [Rn] 5f14 6d10 7s2 7p3
(guess based on bismuth)
Electrons per shell 2, 8, 18, 32, 32, 18, 5
Phase presumably a solid
CAS registry number 54085-64-2

Ununpentium ( IPA: /ˌjuːnʌnˈpɛntiəm/) is the temporary name of a synthetic superheavy element in the periodic table that has the temporary symbol Uup and has the atomic number 115. Multiple isotopes have been made by a fusion of calcium and americium (Uup-288 with the most neutrons). It is expected to be a hard, low-melting metal (around 250 °C) possibly slightly colored and to have diamagnetic properties like bismuth. It can be referred to as eka-bismuth.

Element 115 also falls in the centre of the theoretical island of stability. Although no stable isotopes have yet been found, conventional models predict that if stable isotopes of element 115 can be produced, they will most likely need the "magic number" of 184 neutrons, which would be Uup-299. The currently fabricated isotopes only had at most 173 neutrons (Uup-288), which is far short of 184 neutrons.


On February 2, 2004, the synthesis of ununpentium and ununtrium were reported in Physical Review C by a team composed of Russian scientists at Dubna University's Joint Institute for Nuclear Research and American scientists at the Lawrence Livermore National Laboratory.

The team reported that they bombarded americium (element 95) with calcium (element 20) to produce four atoms of ununpentium (element 115). These atoms, they report, alpha decayed to ununtrium (element 113) in approximately 100 milliseconds. The ununtrium produced then existed for 1.2 seconds before decaying into natural elements.

The synthesizing of the element also reported by scientists of Japan.

In May 2006 in the Joint Institute for Nuclear Research the synthesis of this element was confirmed by another method (the chemical identifying on final products of decay of element).

Ununpentium is a temporary IUPAC systematic element name. Element 115 is also sometimes called eka-bismuth.

Chemical properties

Although element 115 is in the same group as bismuth, its chemistry will be strongly altered by relativistic effects, so it will be somewhat unique in the periodic table. One important difference from bismuth is the presence a stable oxidation state of I, and a Uup+ ion with a chemistry similar to Tl+.

In popular culture

Ununpentium has been theorized to be inside the island of stability. This probably explains why it was mentioned regularly in popular culture, especially in UFO conspiracy theories.

See ununpentium's entries at fictional applications of real materials.

The most popular account of element 115, from Bob Lazar, is considered pseudoscience . Although it is reasonable to suppose that element 115 will have unique properties, there is no openly available empirical evidence to back up Lazar's claims.

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