Solid phase
Official name
Ammonium chloride (beta-, phase II)
Secondary names
Sal ammoniac; Salmiac; Salmiak; NH4Cl; NH4Cl-II; beta-NH4Cl; NH4+Cl-; ClH4N
CAS number
12125-02-9
Type
Family
ionic solid
Class
normal salt
Compound type
chloride
Chemical composition
Formula
$NH_4^+ \cdot Cl^-$
Chemical formula
NH4Cl
Elemental formula
(N+) H4 (Cl-)
Isotope mixture type
terrestrial abundance
4.0
  Formula Name Family Number min-max Mole fraction Isotope mole fraction State Relevance
$NH_4^+$ Ammonium ion molecule 1 0.5 1 constituent cation main
$Cl^-$ Chloride anion element 1 0.5 1 constituent anion main
Chemical functions
  Function Number
$H_4 >\mid N^+$ 1
Chemical bonds
  Bond Number
$>\mid N^+ \cdot Cl^{-}$ 1
$\geq N^+-H$ 4
Class
normal salts (07)
Type
simple normal salts (07.01)
Group
chloride (07.01.03)
Phase name
beta-NH4Cl (phase II)
Phase type
crystalline
Crystal system
isometric (cubic)
Crystal class
hexoctahedral
Crystal class symbol
m-3m (Oh)
Crystal spacegroup
Pm-3m
Comments
disordered orientation of $NH_4^+$ : two possible $NH_4^+$ orientations (Fig. 1a) A and B which are randomly distributed
Molar mass
53.49 $g/mol$
Density
1.519 $g/cm^3$
State NTP
solid
Phase transitions
Phase transition type Other phases Temperature - Pressure
solid-gas gas decomposition 337.6 °C (610.8 k) at 1 atm
solid-solid delta-NH4Cl (phase IV) below -30.4°C (242.8K)
Refringence type
isotropic
Refraction index $n_{\alpha}$
1.642
Pure color
colorless
Color
colorless, white
Diaphaneity
transparent to translucent
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