Solid phase
Official name
Magnesium(II) sulfate monohydrate
Secondary names
Magnesium sulphate monohydrate
CAS number
14168-73-1
Type
Family
ionic solid
Class
normal salt
Compound type
sulfate
Comments
Magnesium sulfate monohydrate occurs as a mineral: Kieserite
Chemical composition
Formula
$Mg^{2+} \cdot SO_4^{2-} \bullet H_2O$
Chemical formula
MgSO4•H2O
Elemental formula
(Mg2+) S O3 (O-)2 H2
Isotope mixture type
terrestrial abundance
6.0
  Formula Name Family Number min-max Mole fraction Isotope mole fraction State Relevance
$Mg^{2+}$ Magnesium(II) cation element 1 0.3333333333333333 1 constituent cation main
$(SO_4)^{2-}$ Sulfate anion chemical function 1 0.3333333333333333 1 anionic radical main
$H_2O$ Water molecule 1 0.3333333333333333 1 hydration main
Chemical functions
  Function Number
$(SO_4)^{2-}$ 1
$R-OH$ 2
Chemical bonds
  Bond Number
$\cdot Mg^{2+} \cdot O^{-}-$ 2
$-O \dots H-$ 2
$-O-H$ 2
$\dddot - \dddot - \dddot - S \dddot - O^{-1/2}$ 4
Class
normal salts (07)
Type
hydrated simple normal salts (07.04)
Equivalent mineral
Kieserite
Phase type
crystalline
Crystal system
monoclinic
Crystal class
prismatic
Crystal class symbol
2/m (C2h)
Crystal spacegroup
C2/c
Molar mass
138.38 $g/mol$
Density
2.445 $g/cm^3$
State NTP
solid
Phase transitions
Phase transition type Other phases Temperature - Pressure
solid decomposition $MgSO_4$ 200°C (473 K)
solid-solid MgSO4.6H2O below 68°C (341 K)
solid-solid MgSO4.6H2O above 42% RH
Refringence type
biaxial
Refringence sign
positive
Birefringence
0.064
Refraction index $n_{\alpha}$
1.520
Refraction index $n_{\beta}$
1.533
Refraction index $n_{\gamma}$
1.584
Dispersion V
relatively strong
Pure color
colorless
Color
colorless
Diaphaneity
transparent to translucent
Luster
vitreous
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