Lawrencium (₁₀₃Lr) is a synthetic element, and thus a standard atomic weight cannot be given. Like all synthetic elements, it has no stable isotopes. The first isotope to be synthesized was ²⁵⁸Lr in 1961. There are fourteen known isotopes from ²⁵¹Lr to ²⁶⁶Lr, except ²⁶³Lr and ²⁶⁵Lr, and seven isomers. The longest-lived known isotope is ²⁶⁶Lr with a half-life of 11 hours.

This reaction was studied in a series of experiments in 1976 by Yuri Oganessian and his team at the FLNR. Evidence was provided for the formation of ²⁵³Lr in the 2n exit channel. In 2022, two states (²⁵³Lr and ^253mLr) were found.

This reaction was studied in a series of experiments in 1976 by Yuri Oganessian and his team at the FLNR. In 2022, two states (²⁵¹Lr and ^251mLr) were found.

This reaction was reported in 1984 by Yuri Oganessian at the FLNR. The team was able to detect decays of ²⁴⁶Cf, a descendant of ²⁵⁴Lr.

This reaction was studied in a series of experiments in 1976 by Yuri Oganessian and his team at the FLNR. Results are not readily available.

This reaction has been used to study the spectroscopic properties of ²⁵⁵Lr. The team at GANIL used the reaction in 2003 and the team at the FLNR used it between 2004–2006 to provide further information for the decay scheme of ²⁵⁵Lr. The work provided evidence for an isomeric level in ²⁵⁵Lr.

This reaction was first studied in 1965 by the team at the FLNR. They were able to detect activity with a characteristic decay of 45 seconds, which was assigned to²⁵⁶Lr or ²⁵⁷Lr. Later work suggests an assignment to ²⁵⁶Lr. Further studies in 1968 produced an 8.35–8.60 MeV alpha activity with a half-life of 35 seconds. This activity was also initially assigned to ²⁵⁶Lr or ²⁵⁷Lr and later to solely ²⁵⁶Lr.

This reaction was studied in 1970 by the team at the FLNR. They were able to detect an 8.38 MeV alpha activity with a half-life of 20 s. This was assigned to ²⁵⁵Lr.