Constituent
Name
Se powder
Official name
Selenium
Family
metallic solid
Class
pseudometal (semi-conductor)
Compound type
elemental solid
Comments
There are also /alpha-, /beta- & /gamma- Se phases d containing Se8 rings (monoclinic/prismatic, 2/m (C2h), P2(1)/c)
Constituent abundance in material
Relevance
main - major
Arrangement
single phase
Mass fraction
1.0
Mole fraction
1.0
Chemical composition
Formula
Se
Chemical formula
Se
Elemental formula
Se
Isotope mixture type
terrestrial abundance
  Formula Name Family Number min-max Mole fraction Isotope mole fraction State Relevance
Se Selenium element 1 1.0 1 constituent element main
Composition comments
helical polymeric chains of Se
Chemical bonds
  Bond Number
−Se−Se− 8
Class
pseudometals (14)
Type
homovalent monolayer pseudometals (14.01)
Phase name
gray selenium
Phase type
crystalline
Crystal system
trigonal
Crystal class
trapezohedral
Crystal class symbol
32 (D3)
Crystal spacegroup
P3(1)21
Comments
Chiral hexagonal crystal lattice, that can also have the crystal_spacegroup P3(2)21 (group 154) depending on the chirality.
Texture
polycrystalline
Molar mass
78.971 g/mol
Density
4.81 g/cm3
Refringence type
uniaxial
Refringence sign
positive
Birefringence
1.04
Refraction index nα
3.00
Refraction index nβ
4.04
Color
gray, purple gray, reddish
Diaphaneity
opaque
Luster
submetallic