Magnesite-Siderite series | SSHADE

Processing math: 46%

Mineral phase

IMA name: Magnesite-Siderite series

Name and identifiers

Secondary names: Ferro-magnesite; Magneso-siderite; Magnesium-Iron carbonate series; Mg-Fe carbonate series
IMA Code: Mgs-Sd

Class: non-silicate mineral
Compound type: carbonate
Comments: full miscibility of the solid solution

Chemical composition

Formula: $(Mg^{2+},Fe^{2+})CO_3$
Chemical formula: (Mg,Fe)CO3
Elemental formula: (Mg2+)0-1 (Fe2+)0-1 C O (O-)2
Isotope mixture type: terrestrial abundance

	Formula	Name	Family	Number min-max	Isotope mole fraction	State	Relevance
	$Mg^{2+}$	Magnesium(II) cation	element	0 - 1		constituent cation	main
	$Fe^{2+}$	Iron(II) cation	element	0 - 1		constituent cation	main
	$(CO_3)^{2-}$	Carbonate anion	chemical function	1		anionic radical	main

Composition comments: Mg+Fe=1

Chemical functions and bonds

Chemical functions

	Function	Number
	$(CO_3)^{2-}$	1

Chemical bonds

	Bond	Number
	$\cdot Mg^{2+} \cdot O^{-}-$	n
	$\cdot Fe^{2+} \cdot O^{-}-$	n
	$\dddot - \dddot - C \dddot - O^{-2/3}$	3

Oxides composition

Oxides

Formula	$MgO$	$FeO$	$CO_{2}$
Mass fraction (%)

Classifications

Strunz

Class: carbonates - nitrates (05)
Division: carbonates without additional anions, without H2O (05.A)
Family: Alkali-earth (and other M2+) carbonates (05.AB)
Code: 05.AB.05

Dana

Major class: carbonates, nitrates, borates (V)
Class: anhydrous carbonates (14)
Type: with simple formula A+CO3 (14.01)
Group: Calcite group (Trigonal: R-3c) (14.01.01)

Endmembers and polymorphs

End-members

Crystallography

Phase type: crystalline
Crystal system: trigonal
Crystal class: ditrigonal-scalenohedral
Crystal class symbol: -3m (D3d)
Crystal spacegroup: R-3c

Physical properties

Molar mass: 84.31 - 115.86 $g/mol$
Density: 3.00 - 3.96 $g/cm^3$

Thermodynamical properties

State NTP: solid

Optical properties

Refringence type: uniaxial
Refringence sign: negative
Birefringence: 0.191 - 0.242
Refraction index $n_o$ (w): 1.700 - 1.875
Refraction index $n_e$ (e): 1.509 - 1.633
Dispersion V: very strong to strong
Pure color: colorless to yellow
Color: colorless, white, yellow, yellowish brown, brown, gray, yellowish gray, greenish gray
Diaphaneity: transparent to subtranslucent
Luster: vitreous

Links and Publications

Links