Unbiunium

Unbiunium is a hypothetical (theoretical or imagined) element of the periodic table. It is also known as eka-actinium. Its atomic number should be 121 and it has the symbol Ubu. The name Unbiunium and the symbol Ubu are temporary IUPAC names (meaning "one-two-one" in Latin). This name and symbol exist until a permanent name is decided and the element is created. It is expected to be a F-block element and in a group call the superactinides. It is the third element in the eighth period of the periodic table.

Unbiunium,  ₁₂₁Ubu

General properties
Pronunciation	/ˌuːnbaɪˈuːniəm/ ​(OON-by-OON-ee-əm)
Alternative names	element 121, eka-actinium
Mass number	320 (predicted) (most stable isotope)
Unbiunium in the periodic table
Hydrogen Helium Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon Sodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine Argon Potassium Calcium Scandium Titanium Vanadium Chromium Manganese Iron Cobalt Nickel Copper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Silver Cadmium Indium Tin Antimony Tellurium Iodine Xenon Caesium Barium Lanthanum Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gold Mercury (element) Thallium Lead Bismuth Polonium Astatine Radon Francium Radium Actinium Thorium Protactinium Uranium Neptunium Plutonium Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium Darmstadtium Roentgenium Copernicium Nihonium Flerovium Moscovium Livermorium Tennessine Oganesson Template:Periodic table (32 columns, micro)/119+ — ↑ Ubu ↓ (Usp) unbinilium ← unbiunium → unbibium
Atomic number (Z)	121
Group	unknown group
Period	period 8
Block	g-block
Element category	superactinide
Electron configuration	[Og] 8s2 8p1 (predicted)
Electrons per shell	2, 8, 18, 32, 32, 18, 8, 3 (predicted)
Physical properties
Phase at STP	Ubu: Unknown phase
Melting point	950.15 K ​(677 °C, ​ °F)
Boiling point	1985.15 K ​(1714 °C, ​ °F)
Atomic properties
Oxidation states	(+1), (+3) (predicted)
Ionization energies	1st: 429 (predicted) kJ/mol
Other properties
Natural occurrence	Ubu:
CAS Number	54500-70-8
History
Naming	IUPAC systematic element name
Main isotopes of unbiunium
Iso­tope Abun­dance Half-life (t1/2) Decay mode Pro­duct 320Ubu syn

Creation attempts

The synthesis of unbiunium was first attempted in 1977 by bombarding a target of uranium-238 with copper-65 ions at the GSI Helmholtz Centre for Heavy Ion Research in Darmstadt, Germany:

• ²³⁸U + ⁶⁵Cu → ³⁰³Ubu

No atoms were identified.

Another alternative name is "Lavoisium".