Magnesium(II) sulfate heptahydrate | SSHADE

Processing math: 60%

Solid phase

Official name: Magnesium(II) sulfate heptahydrate

Name and identifiers

Secondary names: Magnesium sulphate heptahydrate
CAS number: 10034-99-8

Family: ionic solid
Class: normal salt
Compound type: sulfate
Comments: Magnesium sulfate heptahydrate occurs as a mineral: Epsomite

Chemical composition

Formula: $Mg^{2+} \cdot SO_4^{2-} \bullet 7H_2O$
Chemical formula: MgSO4•7H2O
Elemental formula: (Mg2+) S O9 (O-)2 H14
Isotope mixture type: terrestrial abundance

18.0

	Formula	Name	Family	Number min-max	Mole fraction	Isotope mole fraction	State	Relevance
	$Mg^{2+}$	Magnesium(II) cation	element	1	0.1111111111111111	1	constituent cation	main
	$(SO_4)^{2-}$	Sulfate anion	chemical function	1	0.1111111111111111	1	anionic radical	main
	$H_2O$	Water	molecule	7	0.7777777777777778	1	hydration	main

Chemical functions and bonds

Chemical functions

	Function	Number
	$(SO_4)^{2-}$	1
	$R-OH$	2

Chemical bonds

	Bond	Number
	$\cdot Mg^{2+} \cdot O^{-}-$	2
	$-O \dots H-$	14
	$-O-H$	2
	$\dddot - \dddot - \dddot - S \dddot - O^{-1/2}$	4

Class: normal salts (07)
Type: hydrated simple normal salts (07.04)

Associated phases

Equivalent mineral: Epsomite

Crystallography

Phase type: crystalline
Crystal system: orthorhombic
Crystal class: disphenoidal
Crystal class symbol: 222 (D2)
Crystal spacegroup: P2(1)2(1)2(1)

Physical properties

Molar mass: 246.48 $g/mol$
Density: 1.68 $g/cm^3$

Thermodynamical properties

State NTP

solid

Phase transitions

Phase transition type	Other phases	Temperature - Pressure
solid-solid	MgSO4.6H2O + H2O	above 48°C (321 K)
solid-solid	MgSO4.6H2O + H2O	below 51% RH
solid-solid	MgSO4.11H2O	below 2°C (275 K)
solid-solid	MgSO4.11H2O	above ? % RH

Optical properties

Refringence type: biaxial
Refringence sign: negative
Birefringence: 0.028
Refraction index $n_{\alpha}$: 1.433
Refraction index $n_{\beta}$: 1.455
Refraction index $n_{\gamma}$: 1.461
Dispersion V: none to weak
Pure color: colorless
Color: colorless, white
Diaphaneity: transparent to translucent
Luster: vitreous

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