Atomic Mass78.96
Atomic Number34
Name OriginsGreek, selene = moon
Year Discovered1817
Discovered CreditsDiscovered by J. J. Berzelius at Stockholm, Sweden.
RemarksObtained as a silvery metallic allotrope or red amorphous powder, which is less stable. Burns in air, unaffected by water, dissolves in concentrated nitric acid and alkalies. Used in photoelectric cells, photocopier drums, solar cells, and semiconductors.
Diagnostic TestsNative Se and Se2-: Selenium and selenides are detected by heating the powdered mineral on charcoal and are detected by a very pronounced smell described as radishes or rotting radishes. If the selenium is present in quantities, the blowpipe test evolves a brownish smoke which deposits a silvery coating of SeO2 near the assay. If this coating is touched with the reducing flame, an azure-blue color is evident. The open tube test, selenium yields a white oxide which crystallizes in radiating prisms on the sides, often tinged with reddish selenium. The coating is volatile and will advance depending on the location of the flame. The closed tube test, selenium volatizes and condenses as black globules fused on the inside of the glass which may have a reddish tint in the thinnest portion of the sublimate. Selenates (SeO4)2- and Selenites (SeO3)2-: Fuse a sample on charcoal mixed with with soda (Na2CO3) and charcoal dust in the reducing flame of the blowpipe. The reduction of SeO4 or SeO3 is detected by the radish odor. The azure blue selenium flame test color may be noticeable.
ReferencesEmsley, J., 1991; THE ELEMENTS : Sec. Ed., Clarendon Press, Oxford, 251 p.

Naturally Ocurring Isotopes :

Mass Nuclide Number Natural Abundance Half-life Half-life Unit Decay Mode Decay Mode MeV Decay Mode %
119.904048 74 0.9 % Stable
121.903054 75 0 % 118,5 Days beta - 0,864 100,00
122.904271 76 9.2 % Stable
123.902823 77 7.6 % Stable
124.904433 78 23.7 % Stable
125.903314 80 49.8 % Stable
126.905227 82 8.8 % Stable

108 Minerals sorted by % of Se (Selenium) :

Selenium100.00 %Se
Ferroselite73.87 %FeSe2
Dzharkenite73.87 %FeSe2
Kullerudite72.91 %NiSe2
Hastite72.82 %CoSe2
Trogtalite72.82 %CoSe2
Penroseite72.72 %(Ni,Co,Cu)Se2
Krutaite71.31 %CuSe2
Downeyite71.16 %SeO2
Wilkmanite64.21 %Ni3Se4
Trustedtite64.21 %Ni3Se4
Tyrrellite63.06 %(Cu,Co,Ni)3Se4
IMA2001-00559.74 %PdSe2
Achavalite58.57 %FeSe
Sederholmite57.36 %NiSe
Makinenite57.36 %NiSe
Bornhardtite57.26 %Co++Co+++2Se4
Freboldite57.26 %CoSe
Eskebornite56.95 %CuFeSe2
Klockmannite55.41 %CuSe
Stilleite54.70 %ZnSe
Drysdallite51.40 %Mo(Se,S)2
Laphamite50.54 %As2(Se,S)3
Permingeatite50.27 %Cu3SbSe4
Athabascaite49.85 %Cu5Se4
Antimonselite49.31 %Sb2Se3
Bambollaite48.19 %Cu(Se,Te)2
Mgriite47.15 %Cu3AsS3
Umangite45.31 %Cu3Se2
Chameanite44.74 %(Cu,Fe)4As(Se,S)4
Sudovikovite44.74 %PtSe2
Cadmoselite41.26 %CdSe
Palladseite39.57 %Pd17Se15
Mandarinoite39.44 %Fe+++2Se3O96(H2O)
Berzelianite38.32 %Cu2Se
Bellidoite38.32 %Cu2Se
Giraudite37.68 %(Cu,Zn,Ag)12(As,Sb)4(Se,S)13
Jolliffeite37.13 %(Ni,Co)AsSe
Chrisstanleyite37.12 %Ag2Pd3Se4
Guanajuatite36.17 %Bi2Se3
Ahlfeldite35.61 %(Ni,Co)SeO32(H2O)
Cobaltomenite35.58 %CoSeO32(H2O)
Geffroyite35.30 %(Ag,Cu,Fe)9(Se,S)8
Chalcomenite34.86 %CuSeO32(H2O)
Clinochalcomenite34.86 %CuSeO32(H2O)
Sabatierite34.06 %Cu4TlSe3
Hakite33.83 %(Cu,Hg)3(Sb,As)(Se,S)3
Crookesite33.57 %Cu7(Tl,Ag)Se4
Bohdanowiczite33.26 %AgBiSe2
Petrovicite32.84 %PbHgCu3BiSe5
IMA2001-06132.84 %Pd8Hg3Se9
Bukovite32.52 %Tl2Cu3FeSe4
IMA1999-02332.52 %Cu2HgSe2
Eucairite31.54 %CuAgSe
Kitkaite29.77 %NiTeSe
Watkinsonite29.64 %PbCu2Bi4(Se,S)8
Tiemannite28.25 %HgSe
Clausthalite27.59 %PbSe
Nevskite27.09 %Bi(Se,S)
Naumannite26.79 %Ag2Se
Platynite26.49 %(Bi,Pb)3(Se,S)4
Paraguanajuatite25.68 %Bi2(Se,S)3
Selenostephanite25.47 %Ag5Sb(Se,S)4
Oosterboschite24.67 %(Pd,Cu)7Se3
Luberoite24.46 %Pt5Se4
Jeromite24.30 %As(S,Se)2
Sophiite24.03 %Zn2(SeO3)Cl2
Ilinskite23.85 %NaCu5O2(SeO3)2Cl
Chloromenite23.85 %Cu9O2(SeO3)4Cl6
Molybdomenite23.63 %PbSeO3
Georgbokiite23.41 %Cu5O2(SeO3)2Cl2
Fischesserite23.28 %Ag3AuSe2
Skippenite23.24 %Bi2Se2(Te,S)
Kerstenite22.55 %PbSeO4 (?)
Francisite21.90 %Cu3Bi(SeO3)2O2Cl
Demesmaekerite21.81 %Pb2Cu5(UO2)2(SeO3)6(OH)62(H2O)
Padmaite20.02 %PdBiSe
Carlosruizite19.93 %K6(Na,K)4Na6Mg10(Se++++++O4)12(IO3)1212(H2O)
Schmiederite17.96 %Pb2Cu++2(Se++++O3)(Se++++++O4)(OH)4
Derriksite17.94 %Cu4(UO2)(SeO3)2(OH)6
Vihorlatite17.36 %Bi8+x(Se,Te,S)11-x
Laitakarite17.12 %Bi4(Se,S)3
Poubaite15.94 %PbBi2Se2(Te,S)2
Soucekite14.99 %PbCuBi(S,Se)3
Telluronevskite14.94 %Bi3TeSe2
Aguilarite14.55 %Ag4SeS
Haynesite13.29 %(UO2)3(SeO3)2(OH)25(H2O)
Piretite12.69 %Ca(UO2)3(SeO3)2(OH)4-4(H2O)
Wittite12.55 %Pb3Bi4(S,Se)9
Guilleminite12.27 %Ba(UO2)3(SeO3)2O23(H2O)
Marthozite12.11 %Cu[(UO2)3(SeO3)2O2]8(H2O)
Olsacherite12.08 %Pb2(SeO4)(SO4)
Proudite12.03 %(Pb,Cu)8Bi9-10(S,Se)22
Nordstromite11.34 %Pb3CuBi7(S10Se4)
Penzhinite10.40 %(Ag,Cu)4Au(S,Se)4
Junoite10.12 %Pb3Cu2Bi8(S,Se)16
Kawazulite9.76 %Bi2(Te,Se,S)3
Orlandiite8.78 %Pb3(Cl,OH)4(SeO3)(H2O)
Weibullite8.58 %Pb6Bi8(S,Se)18
Babkinite8.09 %Pb2Bi2(S,Se)3
IMA2000-0507.35 %KCdCu7O2(SeO3)2Cl9
Kurilite6.51 %(Ag,Au)2(Te,Se,S)
Ikunolite6.12 %Bi4(S,Se)3
Crerarite4.94 %(Pt,Pb)Bi3(S,Se)4-x (x~0.7)
Pekoite4.87 %PbCuBi11(S,Se)18
Tsnigriite2.48 %Ag9SbTe3(S,Se)3
Mozgovaite1.54 %PbBi4(S,Se)7
Petrovskaite1.16 %AuAg(S,Se)