Solid phase
Official name
Ammonium sulfate (phase FE)
Secondary names
Ammonium sulphate; Ammonium sulfate (2:1); Diammonium sulfate; Sulfuric acid diammonium salt; Mascagnite; Actamaster; Dolamin; Ammoniumsulfate; (NH4)2SO4; FE-(NH4)2SO4; (NH4+)2 SO42-; H8N2O4S
CAS number
7783-20-2
Type
Family
ionic solid
Class
normal salt
Compound type
sulfate
Chemical composition
Formula
$(NH_4^+)_2 \cdot SO_4^{2-}$
Chemical formula
(NH4)2SO4
Elemental formula
(N+)2 H8 S O2 (O-)2
Isotope mixture type
terrestrial abundance
6.0
  Formula Name Family Number min-max Mole fraction Isotope mole fraction State Relevance
$NH_4^+$ Ammonium ion molecule 2 0.6666666666666666 1 constituent cation main
$SO_4^{2-}$ Sulfate ion molecule 1 0.3333333333333333 1 constituent anion main
Chemical functions
  Function Number
$H_4 >\mid N^+$ 2
$(SO_4)^{2-}$ 1
Chemical bonds
  Bond Number
$>\mid N^+ \cdot O^{-}-$ 2
$\geq N^+-H$ 4
$-\gg S-O^{-}$ 2
$\geqq S=O$ 2
$\dddot - \dddot - \dddot - S \dddot - O^{-1/2}$ 4
Class
normal salts (07)
Type
simple normal salts (07.01)
Group
sulfate (07.01.09)
Phase name
FE-Ammonium sulfate
Phase type
crystalline
Crystal system
orthorhombic
Crystal class
pyramidal
Crystal class symbol
mm2 (C2v)
Crystal spacegroup
Pna2(1)
Comments
ferroelectric phase
Molar mass
132.14 $g/mol$
State NTP
solid
Phase transitions
Phase transition type Other phases Temperature - Pressure
solid-solid PE-(NH4)2SO4 above -50°C (223 K)
Phase transitions comments
paraelectric-ferroelectric phase transition at 223K
Refringence type
biaxial
Refringence sign
positive
Birefringence
0.013
Refraction index $n_{\alpha}$
1.521
Refraction index $n_{\beta}$
1.523
Refraction index $n_{\gamma}$
1.533
Pure color
colorless
Color
colorless, white
Diaphaneity
transparent to translucent
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