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PolskiVSEPR Molecular Geometry Lab (2D)
A 2D companion to the VSEPR molecule builder: the same electron-pair repulsion physics on a sphere, drawn as a drag-to-rotate orthographic projection so you can read bond angles and shapes without a full 3D scene.
This 2D companion drives the exact same electron-pair repulsion model as the 3D VSEPR lab — bonding and lone pairs behave as mutually repelling point charges constrained to a sphere, with lone pairs weighted to repel 1.35x harder than bonding pairs — but instead of a full WebGL scene it draws the result as an orthographic projection you rotate by dragging, with nearer atoms drawn larger and brighter so depth reads clearly on a flat canvas. Pick a preset molecule like water or xenon tetrafluoride, or set any bonding/lone-pair combination directly, and watch the live bond-angle readout confirm why lone pairs compress real molecular geometry below the idealized angle.
The same Thomson-problem-style repulsion physics as the 3D version (points on a unit sphere, tangential force projection, lone-pair weighting), rendered as a 2D orthographic projection with depth-based shading instead of a WebGL scene.
2D · HTML5 Canvas 2D · 60 FPS target · runs fully client-side, no install
Every bonding and lone electron pair around a central atom is treated as a point charge constrained to the surface of a sphere. Every pair repels every other pair, and the system relaxes into the same tetrahedral, bent, trigonal-bipyramidal and other shapes that VSEPR theory predicts for real molecules.
Lone pairs are held only by the central atom's nucleus, so they spread out more than a bonding pair (which is pulled by two nuclei). The simulation gives lone pairs 1.35x the repulsive weight of a bonding pair, which is why water's H-O-H angle settles near 104.5° instead of the ideal 109.5°.
The underlying physics is identical — the same sphere-constrained repulsion model — but this page renders it as a 2D orthographic projection you rotate by dragging, instead of a full WebGL scene, so it loads lighter and reads more like a diagram.