Reactions of niobium and tantalum hexanuclear halide clusters with cadmium(II) halides, diamagnetic and paramagnetic clusters with semiconducting properties
| Autor: | Nevenka Brničević, Ida Dunja Desnica-Franković, Marko Miljak, Marija Vojnović, Ivan Bašic, Rudolf Trojko |
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| Rok vydání: | 2001 |
| Předmět: |
Octahedral cluster
Hydrogen bond Chemistry Stereochemistry Mechanical Engineering Crystal structure Condensed Matter Physics Crystal Crystallography Paramagnetism Mechanics of Materials Molecule Antiferromagnetism General Materials Science Hydrate Cluster Compounds Cadmium(II) Halides diamagnetic paramagnetic Semiconducting |
| Zdroj: | Materials Research Bulletin. 36:211-225 |
| ISSN: | 0025-5408 |
| DOI: | 10.1016/s0025-5408(01)00510-4 |
| Popis: | The diamagnetic [Ta 6 Cl 12 (H 2 O) 6 ][CdCl 2 X 2 ]·12H 2 O (X = Br, I) 1 , 2 and [M 6 Br 12 (H 2 O) 6 ][CdBr 2 X 2 ]·12H 2 O (M = Nb, Ta; X = Cl, Br, I) 3–8 clusters as well as paramagnetic [(Ta 6 Cl 12 )Cl(H 2 O) 5 ][CdBr 4 ]·6H 2 O 9 have been isolated. The crystal structures have been determined for [Nb 6 Br 12 (H 2 O) 6 ][CdBr 4 ]·12H 2 O 4 , [Ta 6 Br 12 (H 2 O) 6 ][CdBr 4 ]·12H 2 O 7 and [(Ta 6 Cl 12 )Cl(H 2 O) 5 ][CdBr 4 ]·6H 2 O 9 . Octahedral cluster cations [M 6 Br 12 (H 2 O) 6 ] 2+ in 4 , 7 and [(Ta 6 Cl 12 )Cl(H 2 O) 5 ] 2+ in 9 , together with [CdBr 4 ] 2− anion as discrete units are main structural building blocks. The crystal packing of the cations and anions in a three-dimensional network in 4 and 7 is realized via hydrogen bonds involving crystal and coordinated water molecules and Br − atoms from [CdBr 4 ] 2− anions. The paramagnetic cluster 9 displays the quazionedimensional magnetic properties with intrachain antiferromagnetic interaction J = 68 K and the interchain interaction J’ = 21 K. All compounds show semiconducting properties. The respective activation energies, E a1 = 0.23 eV and E a2 = 0.19 eV (the same values for 7 and 9 ) have been found. |
| Databáze: | OpenAIRE |
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