MolDraw › 3D molecule models › Oxygen 3D model
Oxygen molecule model (O2)
The oxygen molecule, O₂, is two oxygen atoms joined by a double bond (bond order 2). Molecular orbital theory shows it has two unpaired electrons, which makes liquid oxygen magnetic.
Drag to rotate · pinch or scroll to zoom. 3D coordinates: PubChem conformer (CID 977).
Oxygen at a glance
| Formula | O2 |
|---|---|
| Molar mass | 31.999 g/mol |
| IUPAC name | molecular oxygen |
| Atoms / bonds | 2 / 1 |
| H-bond donors / acceptors | 0 / 2 |
| XLogP3 | -1.1 |
| SMILES | O=O |
| PubChem CID | 977 |
What the 3D model of Oxygen shows
The model contains 2 atoms (2 heavy atoms and 0 hydrogens) joined by 1 bonds; in ball-and-stick mode every stick is one bond, and double or aromatic bonds are drawn as multiple sticks. Switch to space-filling to see the molecule as its electron cloud, scaled to van der Waals radii: this is the shape other molecules actually "feel". It can donate 0 and accept 2 hydrogen bonds, and its PubChem XLogP3 of -1.1 means it is very water-loving (hydrophilic). Its topological polar surface area is 34.1 Ų.
Shape and bond angles
| Atom(s) | Geometry / hybridisation | Angles & lengths |
|---|---|---|
| O=O | Linear diatomic | O=O bond length 121 pm, bond energy 498 kJ/mol |
Is Oxygen polar?
Nonpolar: both atoms are identical, so electrons are shared equally.
Elemental composition of O2
| Element | Atoms | Mass (g/mol) | Mass % |
|---|---|---|---|
| Oxygen (O) | 2 | 31.998 | 100.00% |
Calculated from IUPAC standard atomic weights. Check any formula with the molar mass calculator.
Uses of oxygen
- Respiration and medical oxygen
- Steelmaking (basic oxygen furnace)
- Oxy-acetylene welding and rocket oxidiser (liquid O₂)
Interesting facts
- O₂ is paramagnetic: liquid oxygen sticks between the poles of a strong magnet.
- A simple Lewis structure (O=O, all electrons paired) cannot explain this. MO theory puts two unpaired electrons in π* orbitals.
- Oxygen makes up about 21% of dry air by volume.
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Open MolDraw editorFrequently asked questions
Does O₂ have a double bond?
Yes, the bond order is 2. MO theory describes it as a σ bond plus two half-π contributions with two unpaired electrons.
Why is oxygen paramagnetic?
Its two highest-energy electrons occupy two different π* orbitals with parallel spins (a triplet ground state).
What is the chemical formula and molar mass of oxygen?
Oxygen is O2 with a molar mass of 31.999 g/mol (PubChem CID 977). It contains 2 atoms: 2 oxygen.
What is the IUPAC name of Oxygen?
The PubChem-computed IUPAC name is molecular oxygen.
How do I make a model of Oxygen?
Rotate the interactive model above to see how its 2 atoms connect, then copy it with a ball-and-stick kit: use the CPK colours shown (carbon grey or black, hydrogen white, oxygen red, nitrogen blue). For a school project, foam balls and toothpicks work well.