Selenium Mineral Data

Selenium Mineral Data +

General Selenium Information

Chemical Formula:

Composition:

Molecular Weight = 78.96 gm

Selenium 100.00 % Se

______

100.00 %

Empirical Formula:

Environment:

Low temperature due to sublimation of fumarolic vapors. Oxidation-reduction of selenium-bearing solutions in sandstone U and U-V deposits.

IMA Status:

Valid Species (Pre-IMA) 1828

Locality:

Grants District, McKinley County, New Mexico, USA. Link to MinDat.org Location Data.

Name Origin:

From the Greek, Selene, "goddess of the Moon" to contrast Tellure, "earth".

Synonym:

ICSD 22251

PDF 42-1425

Selen tellurium-Mixture with tellurium

Selenium Image

Images:

Selenium

Comments: Acicular crystals of native Selenium (up to 1 cm in length).
Location: Ronneburg U deposit, Gera district, Thuringia, Germany. Scale: Specimen size 3 cm.
© Thomas Witzke / Abraxas-Verlag

Selenium Crystallography

Axial Ratios:

a:c = 1:1.13467

Cell Dimensions:

a = 4.366, c = 4.954, Z = 3; V = 81.78 Den(Calc)= 4.81

Crystal System:

Trigonal - TrapezohedralH-M Symbol (3 2) Space Group: P 3₁21,P 3₂21

$Help on X Ray Diffraction:$ X Ray Diffraction:

By Intensity(I/I_o): 3(1), 3.78(0.55), 2.072(0.35),

Forms:

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Forms: [ 1 1 1] [ 1 1 0]

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Crystal Structure:

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Wyckoff R W G , Crystal Structures , 1 (1963) p.7-83, Second edition. Interscience Publishers, New York, New York

View Additional jPOWD Structure files for Selenium
[1] [2]

Physical Properties of Selenium

Cleavage:

[0112] Good

Color:

Gray, Purple gray, Reddish.

Density:

4.81

Diaphaniety:

Opaque

Fracture:

Flexible - Flexible fragments.

Habit:

Crystalline - Coarse - Occurs as well-formed coarse sized crystals.

Habit:

Disseminated - Occurs in small, distinct particles dispersed in matrix.

Habit:

Granular - Generally occurs as anhedral to subhedral crystals in matrix.

Hardness:

2 - Gypsum

Luster:

Sub Metallic

Streak:

red

Optical Properties of Selenium

Dichroism (e):

cream white.

Dichroism (w):

brown.

Optical Data:

Uniaxial (+), w=3, e=4.04, bire=1.0400.

RL Anisotrophism:

Very strong.

RL Color:

White in air, darker white to grayish brown in oil, red in transmitted light.

Reflectivity

**Standardized Intensity (100%) Reflection Spectra of Selenium in Air**
λ	R₁	R₂	∑ R₁(λ)	∑ R₂(λ)
400 nm	28.40	38.40
420 nm	27.40	37.80
440 nm	26.40	37.20
460 nm	25.50	36.30
480 nm	24.80	35.40
500 nm	24.30	34.70
520 nm	24.00	34.40
540 nm	24.10	34.10
560 nm	24.40	34.00
580 nm	24.80	33.90
600 nm	25.40	33.80
620 nm	25.80	33.50
640 nm	26.00	33.30
660 nm	25.80	32.90
680 nm	25.20	32.40
700 nm	24.60	31.90

**Calculated Relative Intensity Colors of Selenium in Air**
Relative Intensity	0%	40%	80%	100%	120%	160%	200%	240%	280%	320%	360%
R₁
R₂

Calculated Properties of Selenium

Electron Density:

r_electron=4.14 gm/cc
note: r_Selenium=4.81 gm/cc.

Fermion Index

Fermion Index = 0.076
Boson Index = 0.924

Photoelectric:

PE_Selenium= 81.52 barns/electron
U=PE_Selenium x r_electron= 337.68 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Selenium is Not Radioactive

Selenium Classification

Dana Class:

1.3.4.1 (1)Native Elements

(1.3)with semi-metallic and non-metallic elements

(1.3.4)Dana Group

1.3.4.1 Selenium Se P 3₁21,P 3₂21 3 2

1.3.4.2 Tellurium Te P 3₁21 3 2

Strunz Class:

I/B.03-30 I - Elements

I/B - Semimetals and nonmetals

I/B.03 - Sulfur - Selenium series

I/B.03-10 Sulfur S8 F ddd 2/m 2/m 2/m

I/B.03-20 Rosickyite S P 2/c 2/m

I/B.03-30 Selenium Se P 3₁21,P 3₂21 3 2

I/B.03-40 Tellurium Te P 3₁21 3 2

Other Selenium Information

References:

NAME( Duda&Rejl90) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(AntBidBlaNic1)

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Selenium

Se
Dana No: 1.3.4.1 Strunz No: I/B.03-30
Locality:

Notes: