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LITHOEN

Chemical element

Zirconium

A trace element that concentrates in zircon, a mineral robust enough to survive weathering, transport and metamorphism and to carry a datable record through all of them.

Classification

atomic number
40
symbol
Zr
block
d

How this record is known

3
Settled consensus
Cited as the accepted position of the discipline.

3 of 3 claims on this page cite at least one registered source. Counts describe how each statement is known, not how likely it is to be true.

What Lithoen records

Each claim states how it is known and cites its evidence.

Established40 protons

Zirconium has atomic number 40: its nucleus contains 40 protons, and that is what makes it zirconium.

  • definition basis: Atomic number is definitional: an atom with a different proton count is a different element, whatever else it shares.

Evidence support: Supported by the cited evidence one source

Evidence: Commission on Isotopic Abundances and Atomic Weights (IUPAC) 2024 Primary authority

Established91.222 u

The standard atomic weight of zirconium is 91.222(3), a single value because its isotopic composition does not vary appreciably between normal materials.

  • definition basis: CIAAW Standard Atomic Weights 2024; the parenthesised digits are the uncertainty in the last figures as published.
  • precision note: A property of the element as found in normal materials, not the mass of any individual atom.

Evidence support: Supported by the cited evidence one source

Evidence: Commission on Isotopic Abundances and Atomic Weights (IUPAC) 2024 Primary authority

In the knowledge graph

  • Zirconium essential constituent of Zircon
  • Zirconium preferentially partitions into Zircon

Record last updated 2026-09-06. Corrections follow the published corrections policy; superseded claims are retained, never silently edited.