Atomic orbitals
Short answer: Click the p button in the left rail twice to open the orbital menu. Pick s, p, d or a hybrid set. Click an atom to place the orbital on it, or click empty canvas. Drag the round handle to rotate it, and hold Shift to turn in 15 degree steps.
- Click the orbital button (p) in the left rail. Click it again to open the Atomic orbital tool menu.
- Pick an orbital, for example p orbital (vertical).
- Click an atom to place it there. Or click empty canvas.
- Switch to Select and drag the round handle to rotate it.
Orbital types#
| Menu item | Shape | Typical use |
|---|---|---|
| s orbital | A sphere (circle). | s orbitals, H atoms. |
| p orbital (vertical) | Two lobes, up and down. | p orbitals in π systems and conjugation. |
| p orbital (/) | Two lobes on a diagonal. | A p orbital tilted to one side. |
| p orbital (\) | Two lobes on the other diagonal. | The mirror of the one above. |
| dxy orbital | Four lobes between the axes. | d orbital sets, crystal field pictures. |
| dx²−y² orbital | Four lobes on the axes. | Square planar and octahedral metals. |
| dz² orbital | Two lobes and a ring. | The dz² orbital of a metal. |
| Hybrid lobe (sp, sp², sp³) | One big lobe and a small back lobe. | One hybrid orbital, such as a lone pair orbital. |
| sp orbitals (2) | Two lobes at 180°. | sp carbon in an alkyne. |
| sp² orbitals (3) | Three lobes at 120°. | sp² carbon in an alkene or carbocation. |
| sp³ orbitals (4) | Four lobes, tetrahedral, shown in perspective. | sp³ carbon or nitrogen. |
Two lobe orbitals show the phase. One lobe is shaded and the other is open.
Placing on an atom#
- An orbital placed on an atom is attached to it. It moves when you move the molecule.
- A Hybrid lobe points into the open space next to the atom's bonds, like a lone pair.
- sp, sp² and sp³ sets line their lobes up with the bonds the atom already has.
- s, p and d orbitals keep the fixed direction of the menu item.
Orbital size follows the bond length, so orbitals match your structure.
Rotate, move and remove#
- Rotate: switch to Select, click the orbital and drag its round handle. Hold Shift to snap to 15° steps. An s orbital has no handle.
- Move: drag the orbital body. Drop it near an atom to attach it there. Drop it on empty canvas to free it.
- Remove: click it again with an orbital tool, or select it and press Delete.
Colour#
The orbital uses the current drawing colour when you place it. Pick a colour in Color & style first, then place the orbital. The shaded lobe uses that colour.
Teaching ideas#
- Draw an alkene and put a p orbital (vertical) on each sp² carbon. This shows the π overlap.
- Put sp³ orbitals (4) on a carbon to show a tetrahedral center.
- Put a Hybrid lobe on a nitrogen to show where its lone pair sits. Then add the lone pair dots.
- Draw the five d orbitals side by side for a crystal field lesson.
For energy level diagrams, see the molecular orbital diagram guide and the MO diagram generator. The hybridization guide explains when an atom is sp, sp² or sp³.
Common problems#
| Problem | Fix |
|---|---|
| Clicking an orbital removed it | That is the orbital tool's second click. Switch to Select to move or rotate it. |
| No rotate handle | The orbital is an s orbital, or it is not selected. |
| The orbital does not follow the molecule | It was placed on empty canvas. Drag it onto the atom. |
| The orbital is the wrong colour | Delete it, pick a colour in Color & style, and place it again. |
| I cannot find the orbital tool on a phone | Tap More in the bottom bar. |
Questions and answers
How do I draw a p orbital in MolDraw?
Open the orbital tool in the left rail, pick a p orbital and click an atom. Use p orbital (vertical) for π systems.
How do I rotate an orbital?
Select it with the Select tool and drag its round handle. Hold Shift to turn in 15 degree steps.
Can I draw sp3 hybrid orbitals?
Yes. Pick sp³ orbitals (4) and click a carbon. The four lobes line up with its bonds.
How do I change the colour of an orbital?
Pick a colour in Color & style before you place the orbital. It takes the current drawing colour.
Which d orbitals can I draw?
The menu has dxy, dx²−y² and dz². Rotate dxy to show dxz or dyz.
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