Solid phase
Official name
Chromium hydroxide oxide
Secondary names
Cr(OH)O; gGimaldiite
CAS number
20770-05-2
Family
covalent network solid
Class
tridimentional covalent network solid
Compound type
oxide-hydroxide
Formula
Cr2O3
Chemical formula
Cr(OH)O
Elemental formula
Cr O2 H
Isotope mixture type
terrestrial abundance
8.0
  Formula Name Family Number min-max Mole fraction Isotope mole fraction State Relevance
Cr Chromium element 1 0.25 1 constituent element main
O Oxygen element 2 0.5 1 constituent element main
H Hydrogen element 1 0.25 1 constituent element main
Chemical bonds
  Bond Number
>CrO 2
OH 1
OH 1
Class
sheet covalent networks (10)
Type
one metal and one non-metal atoms sheet networks (10.04)
Equivalent mineral
Grimaldiite
Phase name
alpha-CrOOH
Phase type
crystalline
Crystal system
trigonal
Crystal class
ditrigonal-scalenohedral
Crystal class symbol
-3m (D3d)
Crystal spacegroup
R-3m
Comments
Layer crystal structure, where close-packed CrO,-octahedra are held together by short hydrogen bonds.
Molar mass
85.00 g/mol
Density
4.11 g/cm3
State NTP
solid
Refringence type
uniaxial
Refringence sign
negative
Birefringence
0.18
Refraction index nα
2.155
Refraction index nβ
1.975
Pure color
red
Color
dark red
Diaphaneity
opaque
Luster
metallic