Licence, attribution and provenance for the STL molecular models published by MolGod.
CC BY-SA 4.0 International — https://creativecommons.org/licenses/by-sa/4.0/
This licence permits commercial use and the creation of derivative works. It requires attribution, a link to the licence, and an indication of changes; adaptations must be shared under the same or a compatible licence.
Attribution may be given in any reasonable manner. The following form contains everything the licence requires:
"<name> (CAS <number>) — 3D molecular model" by MolGod Scientific, licensed under CC BY-SA 4.0 International. Converted into a triangulated molecular mesh; atomic coordinates and connectivity unchanged. Source: https://molgod.org/licenses/stl/<CAS>/
Each model has its own permanent record at
https://molgod.org/licenses/stl/{CAS}/ carrying the model
identifier, SHA-256, generation date and the source it was built from.
This license applies to the MolGod-created STL mesh, not automatically to third-party source material.
The geometry these models are built from comes from third-party sources. PubChem aggregates data from many depositors whose individual licence terms differ, so rights must be assessed per source rather than assumed for the aggregate.
Linking to MolGod is a way of giving the attribution the licence already requires — not a separate condition of use. We do not, and may not, impose restrictions beyond the terms of CC BY-SA 4.0 International.
Each STL is generated from a computed 3D conformer: atom spheres use van der Waals radii from Bondi 1964 (10.1021/j100785a001), every value checked against the original publication (Table I, p. 443; Table XIV, p. 449 for K, Mg, Na and Pb), and bonds are rendered as cylinders. Canonical STL files take the radii from the versioned MolGod radius table MG1. The engraved variant is built by a separate pipeline that keeps its own copy of the radii; for every element in the published engraved files the values are identical to MG1 (measured on 7 October 2026), and its file header does not declare a radius table.For Br (1.85 Å) and Si (2.10 Å), later compilations quote values that differ from Bondi’s original table; we use the values printed in the original, and every affected model page lists both, with sources. Atomic coordinates and connectivity are used unchanged — no geometry is modelled, adjusted or inferred. Exception: where no source 3D conformer is available, MolGod Scientific computes a PREDICTED conformer (RDKit ETKDGv3 + force field). Such models are not verified and are labelled “PREDICTED MODEL — NOT VERIFIED” on every page, in the preview image and in the STL file header. Since 8 October 2026 every new STL file is checked by the MolGod mesh validator (watertight, orientable, closed mesh, positive volume) before it is published; a file that fails is not published. Published files, counted from the export manifest: canonical 1,343 of 1,343 passed (1,332 of them checked before publication, the rest re-checked after publication), 984 of 1,343 also independently cross-checked with trimesh and numpy-stl; engraved 1,326 of 1,326 passed, 175 of 1,326 with an additional overlay check. Each model page states which checks were performed for that exact file.
The STL format stores no bond-order or colour metadata; those are recorded in the sidecar next to each file, not in the mesh.