Mineral phase
IMA name
Tschermigite
Type
Class
non-silicate mineral
Compound type
sulfate
Chemical composition
Formula
$(NH_4)Al(SO_4)_2 \bullet 12(H_2O)$
Chemical formula
(NH4)Al(SO4)2•12(H2O)
Elemental formula
(N+) H28 Al S2 O16 (O-)4
Isotope mixture type
terrestrial abundance
  Formula Name Family Number min-max Isotope mole fraction State Relevance
$NH_4^+$ Ammonium ion molecule 1 molecular ion main
$Al$ Aluminium element 1 constituent element main
$(SO_4)^{2-}$ Sulfate anion chemical function 2 anionic radical main
$H_2O$ Water molecule 12 hydration main
Chemical functions
  Function Number
$(SO_4)^{2-}$ 2
$R-OH$ 2
Chemical bonds
  Bond Number
$\geq N^+-H$ 4
$-O-H$ 2
$\dddot - \dddot - \dddot - S \dddot - O^{-1/2}$ 4
Oxides
Formula $Al_{2}O_{3}$ $H_{2}O$ $SO_{3}$
Mass fraction (%) 11.25 47.69 35.32
Oxides comments
N2O5 calculated as (NH4)2O = 5.74%

Strunz

Class
sulfates - chromates - molybdates - tungstates (07)
Division
sulfates (selenates, etc.) without additional anions, with H2O (07.C)
Family
with medium-sized and large cations (07.CC)
Code
07.CC.20

Dana

Major class
sulfates, chromates, selenates (VI)
Class
hydrated acid and sulfates (29)
Type
where AB(XO4)2.x(H2O) (29.05)
Group
Alum group (29.05.05)
Code
29.05.05.03
Phase type
crystalline
Crystal system
isometric (cubic)
Crystal class
diploidal
Crystal class symbol
m-3 (Th)
Crystal spacegroup
Pa-3
Molar mass
453.33 $g/mol$
Density
1.65 $g/cm^3$
State NTP
solid
Refringence type
isotropic
Refraction index $n_{\alpha}$
1.459
Pure color
colorless
Color
white, colorless
Diaphaneity
transparent to translucent
Luster
vitreous
Links