Meitnerium · Mt Meitnerium
is a synthetic superheavy element whose properties mostly rely on experiments with a small number of atoms and theoretical predictions.
- atomic number / Atomic number
- 109
- atomic weight / Atomic mass
- 277.154 u
- Family/Group
- 9
- Period · Block / Period · Block
- 7 · d
- Category / Category
- transition metal · Transition metal
- State / State
- solid state
- Electron configuration
- [Rn]7s2 5f14 6d7 (calculated)
- Oxidation states / Oxidation states
- 9, 8, 6, 4, 3, 1
- Electronegativity / Electronegativity
- not included
- Density / Density
- not included
- Melting point / Melting point
- not included
- Boiling point / Boiling point
- not included
- Atomic radius / Atomic radius
- not included
- First ionization energy
- not included
- Discovery year / Discovery
- 1982
attribute description and data source
properties taken from PubChem periodic table snapshot (2026-10-04). Atomic weights may be reference values or representative isotope masses and cannot be considered exact constants for all samples; density, phase transition points, and phase states depend on temperature, pressure, and allotropes. The solidification of helium requires pressure. Some properties of radioactive and superheavy elements are predicted values, and missing items are marked as not included. Please check the original source and experimental conditions for precise calculations.