Welcome back element 118 (ununoctium)
Experiments conducted at the Flerov Laboratory of Nuclear Reactions (Joint Institute for Nuclear Research) at Dubna in Russia indicate that element 118 (ununoctium, Uuo) was produced. Not too much though, one atom in the spring of 2002 and two more in 2005.1,2
The 2002 experiment involved firing a beam of 4820Ca at 24998Cf. The experiment took 4 months and involved a beam of 2.5 x 1019 calcium ions to produce the single event believed to be the synthesis of 294118Uuo.
24998Cf + 4820Ca → 294118Uuo + 31n
This ununoctium isotope loses three alpha particles in rapid succesion:
294118Uuo → 290116Uuh + 42He (1.29 milliseconds)
290116Uuh → 286114Uuq + 42He (14.4 milliseconds)
286114Uuq → 282112Uub + 42He (230 milliseconds)
The 282112Uub species then undergoes spontaneous fragmentation (denoted SF) to other species. It took a few years to carry out enough research to properly characterize the decompoition products.
In 2005 a similar experiment but with more sensitive detectors and a total beam dose of 1.6 x 1019 calcium ions resulted in the detection of two further events arising from the formation of 294118Uuo.
This work is particularly significant given the scandal associated with the first report (now withdrawn) of element 118.
- 1. Synthesis of the isotopes of elements 118 and 116 in the Cf249 and Cm245+Ca48 fusion reactions,
, Physical Review C, 10/2006, Volume 74, Issue 4, (2006)
- 2. Synthesis and decay properties of superheavy elements,
, Pure and Applied Chemistry, 2006, Volume 78, Issue 5, p.889 - 904, (2006)