Compound reference
Ammonia
NH₃
The chemistry
One lone pair on N pushes the three N–H bonds down into a pyramid. That lone pair also makes ammonia a base - it will grab a proton to become NH₄⁺.
Remember it as…
Three bonds + one lone pair → trigonal pyramidal at ~107°. The pair on top is the basicity.
Common mix-up
NH₃ is NOT trigonal planar like BF₃. Both have three bonds, but nitrogen's lone pair tips the tripod into a pyramid and squeezes the H–N–H angle below 109.5°.
Where the name comes from
From sal ammoniac, a salt named after the Egyptian temple of Amun where it was first collected. The "-onia" ending is the same one as in pneumonia (Greek for "lung-stuff").
Where you meet it
Pungent gas; a major industrial chemical (Haber–Bosch process) and the foundation of synthetic nitrogen fertilizer that feeds half the world.
PubChem facts
- IUPAC name
- azane
- Molecular weight
- 17.031 g/mol
Also known as: ammonia gas, spirit of hartshorn
Handling note
A sharp-smelling, corrosive gas that irritates the eyes, skin, and lungs, and is toxic to breathe in concentration.
BondingMolecular geometry
Chemical data from PubChem (NIH/NCBI)