Livermorium (₁₁₆Lv) is a synthetic element, and thus a standard atomic weight cannot be given. Like all artificial elements, it has no stable isotopes. The first isotope to be synthesized was ²⁹³Lv in 2000. There are six known radioisotopes, with mass numbers 288–293, as well as a few suggestive indications of a possible heavier isotope ²⁹⁴Lv. The longest-lived known isotope is ²⁹³Lv with a half-life of 57 ms.

The below table contains various combinations of targets and projectiles which could be used to form compound nuclei with atomic number 116.

In 1995, the team at GSI attempted the synthesis of ²⁹⁰Lv as a radiative capture (x=0) product. No atoms were detected during a six-week experimental run, reaching a cross section limit of 3 pb.

This section deals with the synthesis of nuclei of livermorium by so-called "hot" fusion reactions. These are processes which create compound nuclei at high excitation energy (~40–50 MeV, hence "hot"), leading to a reduced probability of survival from fission. The excited nucleus then decays to the ground state via the emission of 3–5 neutrons. Fusion reactions utilizing ⁴⁸Ca nuclei usually produce compound nuclei with intermediate excitation energies (~30–35 MeV) and are sometimes referred to as "warm" fusion reactions. This leads, in part, to relatively high yields from these reactions.

There are sketchy indications that this reaction was attempted by the team at GSI in 2006. There are no published results on the outcome, presumably indicating that no atoms were detected. This is expected from a study of the systematics of cross sections for ²³⁸U targets.

In 2023, this reaction was studied again at the JINR's Superheavy Element Factory in Dubna, in preparation for a future synthesis attempt of element 120 using ⁵⁴Cr projectiles. One atom of ²⁸⁸Lv was reported; it underwent alpha decay with a lifetime of less than 1 millisecond. The cross-section was measured as 36+46
−24 fb for the 4n channel.

In 2024, this reaction was performed at the LBNL, in preparation for a future synthesis attempt of element 120 using ⁵⁰Ti projectiles. Two atoms of the known isotope ²⁹⁰Lv were successfully produced. This was the first successful synthesis of a superheavy element using ⁵⁰Ti projectiles and an actinide target; the cross-section was reported to be 0.44+0.58
−0.28 pb.

In 2024, this reaction was studied at the JINR, as a next step after the successful ²³⁸U+⁵⁴Cr reaction. Two atoms of ²⁸⁸Lv were detected, as well as three atoms of the new alpha-decaying isotope ²⁸⁹Lv. One atom of ²⁸⁹Mc was found in the p2n channel, which was the first time any pxn channel had been detected in a reaction of actinides with ⁴⁸Ca, ⁵⁰Ti, or ⁵⁴Cr projectiles. The cross-section was reported to be 320+340
−180 fb for the 3n channel, and 220+270
−150 fb for the 4n channel.