Molecule
Name
Ammonium ion
IUPAC name
Ammonium
Secondary names
Ammonium cation, Ammonium(1+), azanium, NH4+
InChI
InChI=1S/H3N/h1H3/p+1
InChI key
QGZKDVFQNNGYKY-UHFFFAOYSA-O
CAS number
14798-03-9
Formula
$NH_4^+$
Chemical formula
NH4+
Structural formula
[NH4+]
Charge
1
  Atom Name Number
$N^+$ Nitrogen cation 1
$H$ Hydrogen 4
Isotope mixture type
terrestrial abundance
Spin type
equilibrated
Molar mass
18.039 $g/mol$
Protic
protic
Polarity
ionic
Molecule symmetry
Td
Case
spherical-top
Vibrations number
4
Vibrations
Label Mode Bond Symmetry Degeneracy Fundamental frequency Observed frequency Observed frequency Harmonic frequency Activity IR Activity Raman Strength Comments
V1 stretching sym. $NH_4^+$ $A_{1}$ no inactive active
V2 deformation $NH_4^+$ $E$ double inactive active
V3 stretching $NH_4^+$ $F_{2}$ triple 3335.8 active active vs 3357.5 cm^{-1} in Ne matrix
V4 deformation $NH_4^+$ $F_{2}$ triple 1447.2 active inactive vs 1442.5 cm^{-1} in Ne matrix
Comments
from NIST WebBook
Chemical bonds
  Bond Number
$\geq N^+-H$ 4