Elements with an atomic number greater than 103, i.e. elements above lawrencium in the periodic table. So far, elements up to 118 have been detected. Because of the highly radioactive and transient nature of these elements, there has been much dispute about priority of discovery and, consequently, naming of the elements. In 1979 the International Union of Pure and Applied Chemistry (IUPAC) introduced a set of systematic temporary names based on affixes, as shown in the table.
Affix | Number | Symbol |
|---|
nil | 0 | n |
un | 1 | u |
bi | 2 | b |
tri | 3 | t |
quad | 4 | q |
pent | 5 | p |
hex | 6 | h |
sept | 7 | s |
oct | 8 | o |
enn | 9 | e |
All these element names ended in -ium. So, for example, element 109 in this system was called un+nil+enn+ium, i.e. unnilennium, and given the symbol u+n+e, i.e. Une.
One long-standing dispute was about the element 104 (rutherfordium), which was also known as kurchatovium (Ku). There were also disputes between IUPAC and the American Chemical Union about element names. In 1994 IUPAC suggested the following list:
mendelevium (Md, 101)
nobelium (No, 102)
lawrencium (Lr, 103)
dubnium (Db, 104)
joliotium (Jl, 105)
rutherfordium (Rf, 106)
bohrium (Bh, 107)
hahnium (Hn, 108)
meitnerium (Mt, 109)
The ACU favoured a different set of names:
mendelevium (Md, 101)
nobelium (No, 102)
lawrencium (Lr, 103)
rutherfordium (Rf, 104)
hahnium (Ha, 105)
seaborgium (Sg, 106)
nielsbohrium (Ns, 107)
hassium (Hs, 108)
meitnerium (Mt, 109)
A compromise list was adopted by IUPAC in 1997 and is now generally accepted:
mendelevium (Md, 101)
nobelium (No, 102)
lawrencium (Lr, 103)
rutherfordium (Rf, 104)
dubnium (Db, 105)
seaborgium (Sg, 106)
bohrium (Bh, 107)
hassium (Hs, 108)
meitnerium (Mt, 109)
Element 110 was named as darmstadtium (Ds) in 2003, element 111 was named roentgenium (Rg) in 2004, element 112 was named copernicium (Cn) in 2010, element 114 was named flerovium (F1) in 2012, and element 116 was named livermorium (Lv) in 2012. In 2016 the elements 113, 115, 117, and 118 were officially named as: nihonium (Nh, 113), moscovium (Mc, 115), tennessine (Ts, 117), and oganesson (Og, 118). All these elements are unstable and have very short half-lives.