109 Mt 278

Meitnerium

unknown, probably transition metal · period 7 · group 9 · d-block

Meitnerium is a synthetic chemical element with the symbol Mt and atomic number 109. It is an extremely radioactive synthetic element (an element not found in nature, but can be created in a laboratory).

What the numbers say

At standard temperature and pressure Meitnerium is a solid, sitting in period 7, group 9 of the d-block.

First identified in 1982.

Check it against computed structures

The structure search queries the Materials Project, OQMD and the Open Materials Database for computed crystal structures containing Mt — with DFT formation energy, hull stability and band gap where the provider publishes them.

Mt

K 2 · L 8 · M 18 · N 32 · O 32 · P 15 · Q 2

Properties

Atomic number 109
Atomic mass 278 u
Series unknown, probably transition metal
Group 9
Period 7
Block d-block
Phase at STP Solid
Electron configuration *[Rn] 5f¹⁴ 6d⁷ 7s²
Discovered 1982

Other unknown, probably transition metals

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See Mt in context with all 118 elements.

Working with meitnerium in a real design?

Ask the materials chat how Mt behaves in your alloy system, what it does to weldability, and which grades to look at — with the source of every number named.