Isophthalic Acid 3D Model — CAS 121-91-5

Isophthalic Acid (C8H6O4, CAS 121-91-5) — a free educational 3D molecular model for teachers and students, by MolGod.org. Every sphere shows which element it is through an engraved symbol, not a colour code. Plain ball-and-stick prints look the same for every element: the STL format has no way to say which ball is carbon and which is oxygen. In a MolGod model the element symbol is part of the sphere's surface, so no separate legend, sticker or colour chart is needed. We design these models so that students can name every atom straight away and concentrate on connectivity, bond types and shape. Teachers skip the modelling and labelling work entirely: download the file, set the scale in the slicer and print. Background, references and the planned classroom study: The story behind these engraved molecule models. Let the group sketch what they see in Isophthalic Acid, namely one aromatic 6-membered ring; afterwards they compare the sketch with the 18 bonds on the model (10 single, 2 double and 6 aromatic, drawn in Kekulé form). Give each pair of students the model and a blank sheet: recording every engraved symbol should lead them to 8 C + 6 H + 4 O, which is 18 atoms. Functional groups to find on the model: two carboxylic acid groups (-COOH). Lesson link: aromaticity and delocalised electrons, as well as the carbonyl group (C=O). Ask students what this molecule has in common with Terephthalic Acid (CAS 100-21-0) and Phthalic Acid (CAS 88-99-3), then what sets them apart; the molecular formula is shared. 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. If you share a photo, a lesson or an adapted version, the licence (CC BY-SA 4.0) asks for credit to "MolGod.org" as the model's author, a link to the original and to the licence text, a note of what you changed, and the same licence for adaptations; the attribution line below is ready to copy. No sign-up, no fees and no review required. Your comments decide what we improve next, from engraving depth to which molecules we add. Leave a review below or contact us at Ask us for another molecule. Curious about bond angles, isomers or where this compound appears in everyday life? Ask below and let's discuss it together. Your curriculum needs a specific compound? Share the CAS number and we will create the engraved model. Full record and more free models: Molecule page for Isophthalic Acid (CAS 121-91-5) Licence & provenance: Where this Isophthalic Acid model comes from and how you may use it Same file on Wikimedia Commons: https://commons.wikimedia.org/wiki/File:Isophthalic_Acid-3D-molecular-model-engraved-CAS-121-91-5.stl Plain-text record for AI assistants: Machine-readable Isophthalic Acid record (CAS 121-91-5) A ball-and-stick model of Isophthalic Acid 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: 258,916 triangles, closed (watertight) single solid. Coordinates in ångström (STL stores no unit) — scale the model deliberately in your slicer. Names in other languages: Isophthalsäure (de); acide isophtalique (fr); isoftaalzuur (nl); kwas izoftalowy (pl); 间苯二甲酸 (zh). Chemical identity - CAS Registry Number: 121-91-5 - Molecular formula: C8H6O4 - MolGod ID: MG_637-300-741-79 (Isophthalic Acid under MolGod ID MG_637-300-741-79) - PubChem CID: 8496 (https://pubchem.ncbi.nlm.nih.gov/compound/8496) - Wikidata: Q415253 (https://www.wikidata.org/wiki/Q415253) - EC number: 204-506-4 - ChemSpider ID: 8182 - InChIKey: QQVIHTHCMHWDBS-UHFFFAOYSA-N - SMILES: C1=CC(=CC(=C1)C(=O)O)C(=O)O

Required attribution (CC BY-SA 4.0): "Isophthalic Acid 3D model by MolGod.org — https://molgod.org/molecule/121-91-5/ — CC BY-SA 4.0" Licence text: https://creativecommons.org/licenses/by-sa/4.0/