3-Methyl-2-pyrazolin-5-one — CAS 108-26-9

3-Methyl-2-pyrazolin-5-one (C4H6N2O, CAS 108-26-9) — 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. On a typical printed molecule every sphere is the same anonymous ball, since the STL file cannot transmit the usual colour convention. Our answer is to cut each element symbol into its sphere, so the printed object labels itself in any colour of filament. 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. Teachers skip the modelling and labelling work entirely: download the file, set the scale in the slicer and print. Curious about the science behind the engraving? The project page is at The story behind these engraved molecule models. At its heart, 3-Methyl-2-pyrazolin-5-one is built around one 5-membered ring. The model shows 13 bonds: 11 single and 2 double. Hand the model round and let students tally the engraved atoms: 4 C + 6 H + 2 N + 1 O, 13 in total. Team task: with the model in hand, each group marks the amide group (-CO-N<), then writes down what they found. Plan it into a unit on the carbonyl group (C=O). Students can look on the model for the 1 donor and 2 acceptors of hydrogen bonds; both figures are computed. MolGod.org shares these models for free to make chemistry tangible in the classroom. Teachers: pass the model round at the start of the lesson, before showing any diagram. Download it, print it and use it in your teaching. Sharing it somewhere? The licence (CC BY-SA 4.0) needs four things: "MolGod.org" credited as the creator, links to the original and to the licence, a mention of any changes, and adaptations released under the same licence. The attribution text below covers the first two. Nothing else is needed: no account, no cost, no compulsory feedback. Feedback is the most important part of this project: your review in the comments shows us how to improve the whole collection and build better models. Contact: Ask us for another molecule. Join the conversation: comments, questions and classroom stories are all welcome, and you can always contact us for anything more. Teaching a compound we have not modelled yet? Get in touch and we will create a 3D model especially for your class. Full record and more free models: Molecule page for 3-Methyl-2-pyrazolin-5-one (CAS 108-26-9) Licence & provenance: Where this 3-Methyl-2-pyrazolin-5-one model comes from and how you may use it Same file on Wikimedia Commons: https://commons.wikimedia.org/wiki/File:3-Methyl-2-pyrazolin-5-one-3D-molecular-model-engraved-CAS-108-26-9.stl Plain-text record for AI assistants: Machine-readable 3-Methyl-2-pyrazolin-5-one record (CAS 108-26-9) A ball-and-stick model of 3-Methyl-2-pyrazolin-5-one 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: 160,766 triangles, closed (watertight) single solid. Coordinates in ångström (STL stores no unit) — scale the model deliberately in your slicer. Chemical identity - CAS Registry Number: 108-26-9 - Molecular formula: C4H6N2O - Molar mass: 98.10 g/mol (exact mass 98.048012819) - IUPAC name: 3-methyl-1,4-dihydropyrazol-5-one - MolGod ID: MG_819-718-576-10 (3-Methyl-2-pyrazolin-5-one under MolGod ID MG_819-718-576-10) - PubChem CID: 7920 (https://pubchem.ncbi.nlm.nih.gov/compound/7920) - Wikidata: Q27286078 (https://www.wikidata.org/wiki/Q27286078) - EC number: 203-565-3 - ChemSpider ID: 7632 - InChIKey: NHLAPJMCARJFOG-UHFFFAOYSA-N - SMILES: CC1=NNC(=O)C1

Required attribution (CC BY-SA 4.0): "3-Methyl-2-pyrazolin-5-one 3D model by MolGod.org — https://molgod.org/molecule/108-26-9/ — CC BY-SA 4.0" Licence text: https://creativecommons.org/licenses/by-sa/4.0/