Mineral phase
IMA name
Thenardite
Type
Class
non-silicate mineral
Compound type
sulfate
Chemical composition
Formula
$Na_2SO_4 $
Chemical formula
Na2SO4
Elemental formula
Na2 S O4
Isotope mixture type
terrestrial abundance
  Formula Name Family Number min-max Isotope mole fraction State Relevance
$Na$ Sodium element 2 constituent element main
$S$ Sulfur element 1 constituent element main
$O$ Oxygen element 4 constituent element main
Chemical functions
  Function Number
$(SO_4)^{2-}$ 1
Chemical bonds
  Bond Number
$\dddot - \dddot - \dddot - S \dddot - O^{-1/2}$ 4
Oxides
Formula $Na_{2}O$ $SO_{3}$
Mass fraction (%) 43.63 56.37

Strunz

Class
sulfates - chromates - molybdates - tungstates (07)
Division
sulfates (selenates, etc.) without additional anions, without H2O (07.A)
Family
with medium-sized and large cations (07.AC)
Code
07.AC.25

Dana

Major class
sulfates, chromates, selenates (VI)
Class
anhydrous acid and sulfates (28)
Type
where (A+)2XO4 (28.02)
Group
-Thenardite- group (28.02.03)
Code
28.02.03.01
Phase type
crystalline
Crystal system
orthorhombic
Crystal class
dipyramidal
Crystal class symbol
mmm (D2h)
Crystal spacegroup
Fddd
Molar mass
142.04 $g/mol$
Density
2.67-2.7 $g/cm^3$
State NTP
solid
Refringence type
biaxial
Refringence sign
positive
Birefringence
0.013
Refraction index $n_{\alpha}$
1.471
Refraction index $n_{\beta}$
1.477
Refraction index $n_{\gamma}$
1.484
Dispersion V
83
Pure color
white
Color
white, grayish white, yellowish white, reddish white, brownish white
Diaphaneity
transparent
Luster
vitreous
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