Constituent Smectite | SSHADE

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Constituent

Name: Smectite
IMA name: Montmorillonite-Beidellite-Nontronite series

Class: silicate mineral
Compound type: phyllosilicate

Constituent abundance in material

Relevance: main - major
Arrangement: single phase
Mass fraction: 1.0

Chemical composition

Formula: $(Na,Ca_{0.5})_{0.3}(Al,Mg,Fe)_2.(Si,Al)_4O_{10}(OH)_2 \bullet n(H_2O)$
Chemical formula: [(Na)1-x(Ca)0.5(1+x)]0.3[(Al)x(Mg)y(Fe3+)1-x-y]2[(Si)x(Al)1-x]4O10(OH)2•n(H2O)
Elemental formula: (Na)0-0.3 (Ca)0-0.15 (Mg)0-0.35 (Fe3+)0-2 (Al)0.7-2.5 (Si)3.5-4 O12 H2
Isotope mixture type: terrestrial abundance

	Formula	Name	Family	Number min-max	Isotope mole fraction	State	Relevance
	$Na$	Sodium	element	0 - 0.3		constituent element	main
	$Ca$	Calcium	element	0 - 0.15		constituent element	main
	$Mg$	Magnesium	element	0 - 0.35		constituent element	main
	$Fe^{3+}$	Iron(III) cation	element	0 - 2		constituent element	main
	$Al$	Aluminium	element	0.7 - 2.5		constituent element	main
	$Si$	Silicon	element	3.5 - 4		constituent element	main
	$O$	Oxygen	element	12		constituent element	main
	$H$	Hydrogen	element	2		constituent element	main

Composition comments: perfect solid solution - Common impurities: Ti, K

Chemical functions and bonds

Chemical functions

	Function	Number
	$(OH)^-$	2

Chemical bonds

	Bond	Number
	$O^--H$	1

Oxides composition

Oxides

Formula	$Na_{2}O$	$CaO$	$Al_{2}O_{3}$	$MgO$	$Fe_{2}O_{3}$	$SiO_{2}$	$H_{2}O$
Mass fraction (%)

Classifications

Strunz

Class: silicates (09)
Division: phyllosilicate (09.E)
Family: with mica sheets, composed of tetrahedral and octahedral nets (09.EC)
Code: 09.EC.40

Dana

Major class: silicates (VIII)
Class: phyllosilicate sheets of six-membered rings (71)
Type: with 2:1 clays (71.03)
Group: Smectite group (Dioctahedral Smectites) (71.03.01a)

Phase type: crystalline

Crystallography

Crystal system: monoclinic
Crystal class: prismatic
Crystal class symbol: 2/m (C2h)
Crystal spacegroup: C2/m

Texture: monocrystalline

Physical properties

Molar mass: 389.27 - 549.07 $g/mol$
Density: 2.0 - 2.7 $g/cm^3$

Optical properties

Refringence type: biaxial
Refringence sign: negative
Birefringence: 0.015 - 0.035
Refraction index $n_{\alpha}$: 1.485 - 1.58
Refraction index $n_{\beta}$: 1.504 - 1.612
Refraction index $n_{\gamma}$: 1.505 - 1.615
Diaphaneity: translucent to opaque
Luster: earthy