Solid phase
Official name
Magnesium(II) sulfate tetrahydrate
Secondary names
Magnesium sulphate tetrahydrate
CAS number
24378-31-2
Type
Family
ionic solid
Class
normal salt
Compound type
sulfate
Comments
Magnesium sulfate tetrahydrate occurs as a mineral: Starkeyite
Chemical composition
Formula
$Mg^{2+} \cdot SO_4^{2-} \bullet 4H_2O$
Chemical formula
MgSO4•4H2O
Elemental formula
(Mg2+) S O6 (O-)2 H8
Isotope mixture type
terrestrial abundance
12.0
  Formula Name Family Number min-max Mole fraction Isotope mole fraction State Relevance
$Mg^{2+}$ Magnesium(II) cation element 1 0.16666666666666666 1 constituent cation main
$(SO_4)^{2-}$ Sulfate anion chemical function 1 0.16666666666666666 1 anionic radical main
$H_2O$ Water molecule 4 0.6666666666666666 1 hydration main
Chemical functions
  Function Number
$(SO_4)^{2-}$ 1
$R-OH$ 2
Chemical bonds
  Bond Number
$\cdot Mg^{2+} \cdot O^{-}-$ 2
$-O \dots H-$ 8
$-O-H$ 2
$\dddot - \dddot - \dddot - S \dddot - O^{-1/2}$ 4
Class
normal salts (07)
Type
hydrated simple normal salts (07.04)
Equivalent mineral
Starkeyite
Phase type
crystalline
Crystal system
monoclinic
Crystal class
prismatic
Crystal class symbol
2/m (C2h)
Crystal spacegroup
P2(1)/m
Molar mass
192.43 $g/mol$
Density
2.007 $g/cm^3$
State NTP
solid
Refringence type
biaxial
Refringence sign
positive
Birefringence
0.007
Refraction index $n_{\alpha}$
1.49
Refraction index $n_{\beta}$
1.491
Refraction index $n_{\gamma}$
1.497
Pure color
colorless
Color
colorless, white
Diaphaneity
transparent to translucent
Luster
vitreous
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