Sc5Pd4Si6 - crystal structure and Si-29/Sc-45 solid state MAS NMR spectroscopic investigations

Author(s)

Schubert, Lea ^[1] ; Doerenkamp, Carsten ^[2] ; Haverkamp, Sandra ^[3] ; Heletta, Lukas ^[1] ; Eckert, Hellmut ^{[2, 3]} ; Poettgen, Rainer ^[1]

Affiliation

^[1] Univ Munster, Inst Anorgan & Analyt Chem, Corrensstr 30, D-48149 Munster - Germany

^[2] Univ Sao Paulo, Inst Phys Sao Carlos, BR-13566590 Sao Carlos, SP - Brazil

^[3] Univ Munster, Inst Phys Chem, Corrensstr 30, D-48149 Munster - Germany

• Document type: Journal article
• Source: DALTON TRANSACTIONS; v. 47, n. 37, p. 13025-13031, OCT 7 2018.
• Web of Science Citations: 1

Abstract

The silicide Sc5Pd4Si6 was synthesized from the elements by arc-melting. Its structure was refined from single crystal X-ray diffractometer data: Immm, Li5Cu3.75P6 type, a = 397.12(6), b = 945.4(1), c = 1314.4(2) pm, wR(2) = 0.0245, 578 F-2 values and 29 parameters. The palladium atoms have slightly distorted tetrahedral silicon coordination and a condensation of these PdSi4 tetrahedra leads to a two-dimensional substructure which is condensed via Si-2 pairs (234 pm Si-Si), forming the {[}Pd4Si6](-) polyanionic network. The Sc5Pd4Si6 structure contains three crystallographically independent scandium sites with coordinations Sc1@Pd4Si8Sc6, Sc2@Pd6Si6Sc3 and Sc3@Pd4Si6Sc4. Sc5Pd4Si6 is a Pauli paramagnet with a low susceptibility of 2.9(5) x 10(-5) emu mol(-1) at room temperature. The Si-29 MAS-NMR spectrum confirms the presence of two crystallographically distinct sites in a 2:1 ratio. Likewise, the three crystallographic scandium sites are well-differentiated by three Sc-45 MAS NMR signals in the expected 2:2:1 ratio. Unambiguous assignments could be made based on the comparison of the nuclear electric quadrupolar coupling parameters with predicted values from WIEN2k calculations. (AU)

• FAPESP's process: 17/06649-0 - New Optical Materials based on Rare-Earth Doped Oxyfluoride Glasses and Ceramics: Structural Studies by Electron Paramagnetic Resonance Methods
• Grantee: Carsten Doerenkamp
• Support Opportunities: Scholarships in Brazil - Post-Doctoral