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103Lr[266]

Actinides / ELEMENT 103

Lawrencium

Lawrencium is a short-lived element used in research.

Atomic number
103
Isotope mass number
[266]
State
Solid
Group
f series
Period
7

01 / A closer look

Meet Lawrencium

Lawrencium has atomic number 103: every atom of this element contains 103 protons. It belongs to period 7 of the periodic table.

In a neutral atom, the number of electrons equals the number of protons. Isotopes of this element share the same atomic number but have different neutron counts.

02 / Physical properties

Physical properties

Melting point
1900 K
Reference estimate; not an established bulk measurement
Boiling point
Not listed
Density
Not listed
Isotope mass number
[266]

Melting points, boiling points and densities follow RSC fact boxes. Density is referenced to room temperature; consult the source for pressure and allotrope details. These are reference values, not a claim that every value was experimentally measured. Atomic weights follow CIAAW.

Physical-property source: Royal Society of Chemistry ↗ · Reviewed 24 September 2026

Standard atomic weights follow CIAAW 2024 (abridged). Brackets show an isotope mass number from IUPAC 2022, not a standard atomic weight.

03 / Atomic structure

Atomic structure

Electron configuration
[Rn]7s2 5f14 6d1
Oxidation states
+3
Electronegativity · Pauling
1.3
First ionisation energy
Not listed
Atomic radius
Not listed

04 / Where it is found

Where it is found

Artificial synthesis in nuclear experiments.

Production and export figures depend on the commodity and reporting year. No comparable country quantities have been included for this element in this edition.

Elements & Earth

Sources for this element

  1. PubChem — Lawrencium ↗
  2. CIAAW — Abridged Standard Atomic Weights 2024 ↗
  3. IUPAC — Periodic Table 2022 ↗
  4. Royal Society of Chemistry — Lawrencium ↗

Data retrieved 23 September 2026