Practical tools for measured work
Bond angle calculator and geometry guide
Calculate an angle from bond vectors and compare ideal electron-domain geometries.
Calculate the layout, check the diagram, then print the result for the shop or jobsite.
Ideal electron-domain geometries
| Geometry | Electron domains | Ideal angles |
|---|---|---|
| Linear | 2 | 180° |
| Trigonal planar | 3 | 120° |
| Tetrahedral | 4 | 109.4712° |
| Trigonal bipyramidal | 5 | 90°, 120°, 180° |
| Octahedral | 6 | 90°, 180° |
How it works
Construct each vector by subtracting the central atom coordinates from a bonded atom’s coordinates. The bond angle is arccos((a·b)/(|a||b|)). The example perpendicular vectors give 90°. The table lists ideal parent electron-domain geometries; a multiple bond counts as one domain.
Current-input example
The result above uses these exact values. This snapshot is included when the page is printed so the output can be checked against the original measurements.
- First bond vector x
- 1
- First bond vector y
- 0
- First bond vector z
- 0
- Second bond vector x
- 0
- Second bond vector y
- 1
- Second bond vector z
- 0
Primary result: Angle between bonds: 90 °.
Before using the result
- Check the selected mode, units and input values before using the result.
- Read the assumptions and rounding rules; compare the worked example with your intended calculation.
- A numerical result does not supply missing context or change the stated limitations.
Limitations
Both vectors must be nonzero. Ideal electron-domain angles are not exact measured molecular angles. Lone pairs and chemical environment can change actual bond angles; this guide does not infer a three-dimensional structure from a molecular formula.
Frequently asked questions
What should I verify before using this result?
Check the input values, units, dates and assumptions. Compare the method and its stated limits with the source relevant to your task.
Why might the finished result differ?
Results depend on the entered data and the model’s assumptions. Rounding, changing conditions or omitted factors can affect the comparison. Read the limitations before using the result.
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