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LITHOEN

Chemical element

Oxygen

The most abundant element in the Earth’s crust and mantle by atom count, and the framework of nearly every rock-forming mineral. Silicate structures are built of oxygen; everything else occupies the spaces between.

A stacked diagram with chemical element at the base, mineral species above it, mineral group to the side, and rock at the top, with a separate boxed note that ore, commodity and resource are not implied by any of them.
SchematicFour different kinds of thing that ordinary usage runs together. An element is defined by atomic number; a mineral species by structure and composition, and accepted by name; a mineral group gathers species and is not itself a species; a rock is an aggregate of minerals. None of these levels implies an ore, a commodity or a resource.
Full description of this figure

Reading upward: chemical elements, defined by atomic number, with silicon, oxygen, magnesium and iron as examples. Above them, mineral species — naturally occurring, ordered in structure, with a characteristic composition, and accepted under that name by the International Mineralogical Association — with forsterite as an example. Beside them, mineral groups and series, which gather species and are explicitly not species themselves, with olivine as an example. Above, rocks, which are aggregates of one or more minerals, with peridotite as an example. Set apart in a bordered box: ore, commodity and resource, none of which follows from any level below.

Original Lithoen diagram · LITHOEN-ORIGINAL

Classification

atomic number
8
symbol
O
block
p

How this record is known

1
Directly recorded
Observed or measured, reported by the party that made the observation.
4
Settled consensus
Cited as the accepted position of the discipline.

5 of 5 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.

Measured0.00187–0.00222 ratio

The natural abundance of oxygen isotopes is not a universal constant: CIAAW gives oxygen-16 as [0.99738, 0.99776], oxygen-17 as [0.000367, 0.000400] and oxygen-18 as [0.00187, 0.00222], intervals that span the variation found in normal materials.

  • precision note: The interval quoted in the value is for oxygen-18; the other two isotopes are given in the statement.
  • method: Critical evaluation of published isotopic composition measurements by CIAAW.

Evidence support: Supported by the cited evidence one source

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

Established8 protons

Oxygen has atomic number 8: its nucleus contains 8 protons, and that is what makes it oxygen.

  • 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

Established15.99903–15.99977 u

The standard atomic weight of oxygen is given as the interval [15.99903, 15.99977], because its isotopic composition varies measurably between normal materials.

  • definition basis: CIAAW Standard Atomic Weights 2024. An interval is not an uncertainty: it is the range the value genuinely takes across normal materials.
  • precision note: A standard atomic weight is 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

EstablishedA standard atomic weight is a CIAAW-recommended value for an element as found in normal materials; it is neither the mass of a single atom nor a universal constant.

General principle, shown here for context — not an observation about this record.

A standard atomic weight is a CIAAW-recommended value applicable to normal materials — a property of the element as it is actually found, not the mass of a single atom and not a single universal constant.

  • definition basis: CIAAW, Standard Atomic Weights 2024.
  • generality: GENERAL_PRINCIPLE
  • precision note: Corrected in Phase 7. This claim defines what a standard atomic weight IS, and its statement asserts nothing numeric — yet it stored oxygen’s interval 15.99903–15.99977 u under the predicate standardAtomicWeight, so a reader saw a number printed beside prose that never mentions it. That value is separately and correctly held by claim:oxygen-atomic-weight, with a statement that renders it. The definition now carries a text value and is marked as the general principle it always was.

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

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