What is the 3D Molecular Model Viewer?
Quick Answer: Rotate, zoom, and inspect 3D structures of common molecules (water, ammonia, methane, benzene) in ball‑and‑stick or space‑filling style. View bond angles, toggle a net dipole moment arrow, and see atom labels – no plugins required.
Theory of Molecular Geometry (VSEPR)
The VSEPR theory predicts molecular shapes based on electron‑pair repulsion. Water is bent (104.5°), ammonia trigonal pyramidal (107°), methane tetrahedral (109.5°), and benzene a planar hexagon with 120° bond angles. The dipole moment vector indicates overall polarity; it is the sum of bond dipole vectors. This tool renders these shapes to scale and calculates the net dipole for polar molecules.
Step-by-Step Examples
Example 1: Water Geometry
- Select Water. The oxygen (red) is at the center, with two hydrogens (white). The H–O–H bond angle is shown as ~104.5°.
- Enable "Dipole Arrow" to see the net dipole pointing toward the oxygen (negative end).
- Switch to Space‑filling to see how the lone pairs create a "bent" electron cloud shape.
Example 2: Methane Tetrahedral
- Choose Methane. The carbon (black) sits at the center of a tetrahedron with four hydrogens. Bond angles are 109.5°.
- Methane is non‑polar; no net dipole arrow appears even when toggled.
Example 3: Benzene Ring
- Pick Benzene. A planar hexagon of carbons with attached hydrogens. All C–C–C angles are 120°.
- Rotate to see the delocalized π‑system (visualized as a translucent disc in ball‑and‑stick mode).
Frequently Asked Questions
How are bond angles determined?
They are computed directly from the 3D coordinates of the atoms. The measured angle is shown in the overlay for the highlighted bond.
Can I upload my own .mol or .xyz file?
This version includes preset molecules only. Future updates may add file import.
What do the dipole arrow directions represent?
The arrow points from the positive end (+) toward the negative end (−) of the net molecular dipole. It is displayed for polar molecules.
How do I rotate the view?
Drag with left mouse button to rotate, scroll to zoom, right‑click to pan. Touch gestures are also supported.
Are lone pairs shown?
In ball‑and‑stick mode, lone pairs are not explicitly drawn; the VSEPR geometry implies them. Space‑filling models represent the electron cloud indirectly.