Constituent
Name
Romanechite
IMA name
Romanechite
Class
non-silicate mineral
Compound type
oxide-hydroxide
Constituent abundance in material
Relevance
main - major
Arrangement
single phase
Mass fraction
1.0
Chemical composition
Formula
$(Ba,H_2O)_2(Mn^{4+},Mn^{3+})_5O_{10}$
Chemical formula
(Ba,H2O)2(Mn4+,Mn3+)5O10
Elemental formula
(Ba)0-2 (Mn3+)0-5 (Mn4+)0-5 (O)10-12 (H)0-4
Isotope mixture type
terrestrial abundance
  Formula Name Family Number min-max Isotope mole fraction State Relevance
$Ba$ Barium element 0 - 2 constituent element main
$Mn^{3+}$ Manganese(III) cation element 0 - 5 constituent element main
$Mn^{4+}$ Manganese(IV) cation element 0 - 5 constituent element main
$O$ Oxygen element 10 constituent element main
$H_2O$ Water molecule 0 - 2 hydration main
Composition comments
Frequently with some Si (~0.1) replacing Ba and/or Mn
Chemical functions
  Function Number Relevance
$R-OH$ 2 main
Chemical bonds
  Bond Number Relevance
$-O-H$ 2 main
Oxides
Formula $BaO$ $Mn_{2}O_{3}$ $SiO_{2}$ $H_{2}O$
Mass fraction (%) 19.72 69.62 1.1 3.97
Oxides comments
values for $Ba_{0.7}(Mn^{3+})_{4.8}Si_{0.1}O_{10}•1.2(H_2O)$. Si is not a basic element of Romanechite

Strunz

Class
oxides - hydroxides - arsenites (04)
Division
metal:oxygen = 1:2 and similar (04.D)
Family
with large (+/- medium-sized) cations; tunnel structures (04.DK)
Code
04.DK.10

Dana

Major class
oxides and hydroxides (III)
Class
multiple oxides (07)
Type
07.09
Group
-Romanechite- group (07.09.02)
Code
07.09.02.01
Phase type
crystalline
Crystal system
monoclinic
Crystal class
prismatic
Crystal class symbol
2/m (C2h)
Crystal spacegroup
C2/m
Texture
monocrystalline
Molar mass
544.25 $g/mol$
Density
4.7 - 4.74 (calc. 4.90) $g/cm^3$
Refringence type
biaxial
Refringence sign
positive
Color
grayish black, black, steel gray
Diaphaneity
opaque
Luster
submetallic