Lawrencium

Lawrencium is element 103 (Lr), located in period 7, group 3 and the d block. At room temperature its reference phase is solid. Its electron configuration is [Rn] 5f14 7s2 7p1.

Atomic number103

Standard atomic weightNo standard atomic weight

Group3

Period7

Blockd

Electron configuration[Rn] 5f14 7s2 7p1

Electronic structure

What controls its chemistry

The d subshell participates in the chemistry of lawrencium. Transition metals can use electrons of similar energies in bonding, which is why variable oxidation states, coordination compounds and catalytic behaviour are common across the d block.

Its electron configuration, [Rn] 5f14 7s2 7p1, should be read together with the oxidation state of the compound: removing electrons changes which d orbitals are occupied and can alter colour, magnetism, bonding and reactivity.

Chemical forms

Compounds, ions and materials

For lawrencium, important chemical forms include metals and alloys, oxides, halides and coordination compounds. Variable oxidation states are common because s and d electrons have similar energies, and ligands around the metal ion can strongly alter colour, magnetism and reactivity.

Physical behaviour

State and phase changes

The reference phase at room temperature is solid. The melting point is 1 900 K (1 627 °C). Where a phase-transition value is not listed, the behaviour may be poorly defined under ordinary pressure, depend strongly on allotrope, or lack a reliable reference value. Pressure, purity and crystal structure can shift measured physical properties.

Occurrence and applications

Where lawrencium is found and used

In practice, lawrencium is encountered in scientific research.

In practice

Examples of real uses

Scientific research

Lawrencium is produced, isolated or measured mainly to test atomic, nuclear and periodic trends rather than for bulk commercial use.

Periodic position

What its neighbours tell us

Lawrencium is in period 7. In the f-block sequence shown here, it appears between nobelium and rutherfordium. This sequence allows a direct comparison with the neighbouring f-block elements.

Reference data

Physical and atomic properties

Classificationactinide

Phase at room temperatureSolid

Electron shells2 · 8 · 18 · 32 · 32 · 8 · 3

Density—

Melting point1 900 K (1 627 °C)

Boiling point—

Pauling electronegativity1.3

First ionisation energy479kJ/mol

Electron affinity—

Values describe the element or neutral atom where applicable. Physical data can depend on allotrope, pressure and measurement conditions.

History

Discovery and identification

The discovery of lawrencium is associated with Lawrence Berkeley National Laboratory. Recognition of the element, isolation of a pure sample and assignment of its modern atomic number did not necessarily occur at the same time.

Isotopes and atomic weight

How isotope composition changes the numbers

Lawrencium has no standard atomic weight. There is no characteristic terrestrial isotopic mixture from which a stable abundance-weighted average can be assigned.

Lawrencium has no stable isotope. Its isotopes are radioactive, and their half-lives and decay modes become important whenever the element is measured, handled or used.

Safety

Handling and exposure

Lawrencium is radioactive. Work with it requires radiological controls appropriate to the isotope, activity, radiation type and chemical form.