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Publication Type
Journal Article
UWI Author(s)
Author, Analytic
Fender, Nicolette S.; Kahwa, Ishenkumba A.
Author Affiliation, Ana.
Department of Chemistry
Article Title
Defects and luminescence behavior of cubic F23 [(NH4(18-Crown-6)(4)MnX4] [TIX4], (X = Cl, Br) crystals
Medium Designator
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Connective Phrase
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Journal Title
Journal of solid state chemistry
Translated Title
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Reprint Status
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Date of Publication
2002
Volume ID
163
Issue ID
1
Page(s)
286-293
Language
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Connective Phrase
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Location/URL
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ISSN
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Notes
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Abstract
Luminescence from [(NH4(18-Crown-6)(4)MnBr4][TIBr4] (2) (1), [(NH4(18-Crown-6))(4)NH4Cl4][TICl4] (2) (2), [(NH4(18-Crown-6))(2)MnBr4] (3), and [(NH4(18-Crown-6))(2)MnCl4] (4) was studied in search of new insights regarding crystal defects in 2. Emission from 3 and 4 is normal Mn2+(T-4(1)((4)G) --> 6A(1); that of 2 (lambda(max) 520 nm at ca. 300 k and 560 nm at 77 K) is unusual and temperature dependent. Thermal barriers (kj/mol, assignment): green emission of 1 and 2, T < 150 K (1-2, NH4+ rotations), 150 < T < 250 K (7-14, energy migration among [MnX4] (2-)), 250 < T < 300 K (26-35, rotations of 18-Crown-6); yellow emission of 2: T <250 K (7-8, energy migration among [MnX4](2-)), T > 250K (29 kj/mol, defect-to-Mn2+(4T(1)(4)G)) back energy transfer). Crystal data for 4: Space group P2(1)/c; Z = 4; a = 20.173(1) aNGSTROM; B = 9.0144(8) Angstrom; b = 9.0144(8) Angstrom; c= 20.821(1) Angstrom; beta = 98.782(5)degrees; V= 3741.9(8) Angstrom(3); R-w = 0.059; R = 0.054. (C) 2002 Elsevier Science.....
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