It is named after Ernest Lawrence, inventor of the cyclotron, a device that was used to discover many artificial radioactive elements.

A radioactive metal, lawrencium is the eleventh transuranium element, the third transfermium, and the last member of the actinide series.

Chemistry experiments confirm that lawrencium behaves as a heavier homolog to lutetium in the periodic table, and is a trivalent element.

In the 1950s, 1960s, and 1970s, many claims of the synthesis of element 103 of varying quality were made from laboratories in the Soviet Union and the United States.

The International Union of Pure and Applied Chemistry (IUPAC) initially established lawrencium as the official name for the element and gave the American team credit for the discovery; this was reevaluated in 1992, giving both teams shared credit for the discovery but not changing the element's name.

[19] The definition by the IUPAC/IUPAP Joint Working Party (JWP) states that a chemical element can only be recognized as discovered if a nucleus of it has not decayed within 10−14 seconds.

This value was chosen as an estimate of how long it takes a nucleus to acquire electrons and thus display its chemical properties.

[k] In 1958, scientists at Lawrence Berkeley National Laboratory claimed the discovery of element 102, now called nobelium.

While the data agrees reasonably with that later discovered for 257Lr (alpha decay energy 8.87 MeV, half-life 0.6 s), the evidence obtained in this experiment fell far short of the strength required to conclusively demonstrate synthesis of element 103.

[51] The first important work on element 103 was done at Berkeley by the nuclear-physics team of Albert Ghiorso, Torbjørn Sikkeland, Almon Larsh, Robert M. Latimer, and their co-workers on February 14, 1961.

[53] The first atoms of lawrencium were reportedly made by bombarding a three-milligram target consisting of three isotopes of californium with boron-10 and boron-11 nuclei from the Heavy Ion Linear Accelerator (HILAC).

Scientists at Joint Institute for Nuclear Research in Dubna (then in the Soviet Union) raised several criticisms: all but one were answered adequately.

[52] The Berkeley team proposed the name "lawrencium" with symbol "Lw", after Ernest Lawrence, inventor of the cyclotron.

The IUPAC Commission on Nomenclature of Inorganic Chemistry accepted the name, but changed the symbol to "Lr".

[52] In 1971, the IUPAC granted the discovery of lawrencium to the Lawrence Berkeley Laboratory, even though they did not have ideal data for the element's existence.

But in 1992, the IUPAC Transfermium Working Group (TWG) officially recognized the nuclear physics teams at Dubna and Berkeley as co-discoverers of lawrencium, concluding that while the 1961 Berkeley experiments were an important step to lawrencium's discovery, they were not yet fully convincing; and while the 1965, 1968, and 1970 Dubna experiments came very close to the needed level of confidence taken together, only the 1971 Berkeley experiments, which clarified and confirmed previous observations, finally resulted in complete confidence in the discovery of element 103.

In the periodic table, it is to the right of the actinide nobelium, to the left of the 6d transition metal rutherfordium, and under the lanthanide lutetium with which it shares many physical and chemical properties.

Lawrencium is expected to be a solid under normal conditions and have a hexagonal close-packed crystal structure (c/a = 1.58), similar to its lighter congener lutetium, though this is not yet known experimentally.

[62] This makes it unlike the immediately preceding late actinides which are known to be (fermium and mendelevium) or expected to be (nobelium) divalent.

[65] Some scientists prefer to end the actinides with nobelium and consider lawrencium to be the first transition metal of the seventh period.

[70] Studies on the element, performed in 1969, showed that lawrencium reacts with chlorine to form a product that was most likely the trichloride, LrCl3.

In 1970, chemical studies were performed on 1500 atoms of 256Lr, comparing it with divalent (No, Ba, Ra), trivalent (Fm, Cf, Cm, Am, Ac), and tetravalent (Th, Pu) elements.

On the basis of this, the standard electrode potential of the E°(Lr3+ → Lr+) couple was calculated to be less than −1.56 V, indicating that the existence of Lr+ ions in aqueous solution was unlikely.

Hence, unlike thallium but like lutetium, lawrencium would prefer to form LrH3 than LrH, and LrCO is expected to be similar to the also unknown LuCO, both metals having valence configuration σ2π1 in their monocarbonyls.

[77][78] 1974 relativistic calculations concluded that the energy difference between the two configurations was small and that it was uncertain which was the ground state.

[75] Later 1995 calculations concluded that the s2p configuration should be energetically favored, because the spherical s and p1/2 orbitals are nearest to the atomic nucleus and thus move quickly enough that their relativistic mass increases significantly.

[6] This value is the lowest among all the lanthanides and actinides, and supports the s2p configuration as the 7p1/2 electron is expected to be only weakly bound.

[73] As such lawrencium may still be considered to be a d-block element, albeit with an anomalous electron configuration (like chromium or copper), as its chemical behaviour matches expectations for a heavier analogue of lutetium.

[82][86][87] Most isotopes of lawrencium can be produced by bombarding actinide (americium to einsteinium) targets with light ions (from boron to neon).

[89] More recent methods have allowed rapid selective elution with α-HIB to take place in enough time to separate out the longer-lived isotope 260Lr, which can be removed from the catcher foil with 0.05 M hydrochloric acid.