Acetaminophen 3D Molecular Model — CAS 103-90-2

Acetaminophen (C8H9NO2, CAS 103-90-2) — a free educational 3D molecular model for teachers and students, by MolGod.org. Whatever the filament colour, each atom reads clearly thanks to its engraved symbol.

Ordinary molecular STL files leave students guessing, because the colour scheme that identifies atoms on screen does not survive printing. We build the label into the model: each sphere bears its recessed element symbol, readable by eye and by fingertip. Our goal as an education project: free files for teachers, designed so that students recognise atoms at a glance and spend their attention on bonds and structure. No CAD skills are needed on the teacher's side; the structure, geometry and labels come ready in one file. Teachers and researchers can find the project rationale and validation plan at How the engraved atom letters are designed.

Let the group sketch what they see in Acetaminophen, namely one aromatic 6-membered ring; afterwards they compare the sketch with the 20 bonds on the model (13 single, 1 double and 6 aromatic, drawn in Kekulé form). Hand the model round and let students tally the engraved atoms: 8 C + 9 H + 1 N + 2 O, 20 in total. Team task: with the model in hand, each group marks the amide group (-CO-N<) and the phenolic hydroxyl group (Ar-OH), then writes down what they found. Teachers covering aromaticity and delocalised electrons, the carbonyl group (C=O), as well as phenols and hydrogen bonding will find it a concrete example. Same formula, different structure: put it next to 4-Aminophenylacetic acid (CAS 1197-55-3) and Methyl Anthranilate (CAS 134-20-3) from the same collection and ask students what changed.

MolGod.org offers this engraved model free to anyone teaching or learning chemistry. Teachers: use it as a hands-on starter before drawing the structural formula on the board.

Print it, hand it round and build a lesson around it. Publishing pictures, materials or remixes of it? Under CC BY-SA 4.0, name "MolGod.org" as the author, link back to the original and to the licence, mark your changes and keep remixes under the same terms. A ready-made attribution is included below. Nothing else is needed: no account, no cost, no compulsory feedback. Every review helps us refine the models for students. Tell us what you think in the comments, or reach us at Write to the MolGod team. Let's talk chemistry! Ask anything about this structure in the comments, and other teachers are warmly invited to share their lesson ideas. From CAS number to printed molecule: MolGod creates engraved 3D models of any compound on request.

Full record and more free models: Acetaminophen, CAS 103-90-2: structure, properties and 3D viewer
Licence & provenance: Licence record for this Acetaminophen model
Same file on Wikimedia Commons: https://commons.wikimedia.org/wiki/File:Acetaminophen-3D-molecular-model-engraved-CAS-103-90-2.stl
Plain-text record for AI assistants: Acetaminophen data sheet in plain text for LLMs
Also published on: NIH 3D https://3d.nih.gov/entries/3DPX-023797 · Zenodo (DOI, latest version) https://doi.org/10.5281/zenodo.23670633

A ball-and-stick model of Acetaminophen with each element symbol recessed into its atom sphere, generated by MolGod.org from a PubChem-computed 3D conformer (not an experimental crystal structure); atomic coordinates and connectivity are unchanged. STL mesh: 260,694 triangles, closed (watertight) single solid. Coordinates in ångström (STL stores no unit) — scale the model deliberately in your slicer.

Names in other languages: Paracetamol (de); paracétamol (fr); paracetamolo (it); paracetamol (nl); 对乙酰氨基酚 (zh).

Chemical identity

• CAS Registry Number: 103-90-2

• Molecular formula: C8H9NO2

• Molar mass: 151.16 g/mol (exact mass 151.063328530)

• IUPAC name: N-(4-hydroxyphenyl)acetamide

• MolGod ID: MG_106-378-790-33 (Permanent MolGod record MG_106-378-790-33)

• PubChem CID: 1983 (https://pubchem.ncbi.nlm.nih.gov/compound/1983)

• Wikidata: Q57055 (https://www.wikidata.org/wiki/Q57055)

• EC number: 203-157-5

• ChemSpider ID: 1906

• InChIKey: RZVAJINKPMORJF-UHFFFAOYSA-N

• SMILES: CC(=O)NC1=CC=C(C=C1)O

Required attribution (CC BY-SA 4.0): "Acetaminophen 3D model by MolGod.org — https://molgod.org/molecule/103-90-2/ — CC BY-SA 4.0"
Licence text: https://creativecommons.org/licenses/by-sa/4.0/