MolDraw › 3D molecule models › Acetylene structure
Acetylene structure and 3D model (C2H2)
Acetylene (ethyne) is the simplest alkyne: two carbons joined by a C≡C triple bond with one hydrogen on each. All four atoms are in a straight line.
Drag to rotate · pinch or scroll to zoom. 3D coordinates: computed with RDKit (ETKDG conformer, force-field optimised).
Acetylene at a glance
| Formula | C2H2 |
|---|---|
| Molar mass | 26.04 g/mol |
| IUPAC name | acetylene |
| Atoms / bonds | 4 / 3 |
| H-bond donors / acceptors | 0 / 0 |
| logP (estimated) | 0.2 |
| SMILES | C#C |
| InChIKey | HSFWRNGVRCDJHI-UHFFFAOYSA-N |
| PubChem | 6326 |
What the 3D model of Acetylene shows
The model contains 4 atoms (2 heavy atoms and 2 hydrogens) joined by 3 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 0 hydrogen bonds, and its estimated logP of 0.2 means it is fairly balanced between water and fat. Its topological polar surface area is 0 Ų.
Shape and bond angles
| Atom(s) | Geometry / hybridisation | Angles & lengths |
|---|---|---|
| each carbon | Linear, sp | 180° |
| C≡C bond | Triple bond (σ + 2π) | ≈ 1.20 Å |
| C–H bond | Single bond | ≈ 1.06 Å |
Is Acetylene polar?
No. It is linear and symmetric, so it has no net dipole. Its C–H bonds are slightly acidic for a hydrocarbon (pKa about 25).
Elemental composition of C2H2
| Element | Atoms | Mass (g/mol) | Mass % |
|---|---|---|---|
| Carbon (C) | 2 | 24.022 | 92.26% |
| Hydrogen (H) | 2 | 2.016 | 7.74% |
Calculated from IUPAC standard atomic weights. Check any formula with the molar mass calculator.
Uses of acetylene
- Fuel for oxy-acetylene welding and cutting
- Raw material for vinyl chloride and other chemicals
- Was used in carbide lamps for mining and bicycles
Interesting facts
- An oxy-acetylene flame can reach over 3000 °C.
- Acetylene is made by adding water to calcium carbide or by cracking hydrocarbons.
- It is stored dissolved in acetone inside cylinders because compressed pure acetylene can explode.
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Open MolDraw editorFrequently asked questions
What is the structure of Acetylene?
Acetylene (ethyne) is the simplest alkyne: two carbons joined by a C≡C triple bond with one hydrogen on each. All four atoms are in a straight line. Its SMILES is C#C.
Why is acetylene linear?
Each carbon is sp hybridised with two electron domains, which point 180° apart.
Is acetylene the same as ethyne?
Yes. Ethyne is the systematic name; acetylene is the common name and is accepted by IUPAC.
What is the chemical formula and molar mass of Acetylene?
Acetylene is C2H2 with a molar mass of 26.04 g/mol. It contains 4 atoms: 2 carbon, 2 hydrogen.
What is the IUPAC name of Acetylene?
The IUPAC name is acetylene.
How do I draw Acetylene?
Open the MolDraw editor, paste the SMILES C#C or type "Acetylene" in name search, and the structure is drawn for you. You can then export it as PNG, SVG, MOL or CDXML.