Naslov
Octahedral niobium cluster-based solid state halides and oxyhalides : effects of the cluster condensation via an oxygen ligand on electronic and magnetic properties

Autori
Fontaine, Bruno ; Cordier, Stéphane ; Gautier, Régis ; Gulo, Fakhili ; Halet, Jean-François ; Perić, Berislav ; Perrin Christiane

Izvornik
New journal of chemistry (1144-0546) 35 (2011), 10; 2245-2252

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
cluster compounds ; density functional calculations ; magnetic properties ; niobium ; LMTO

Sažetak
The influences of an oxygen ligand on the structural, magnetic and electronic properties of octahedral niobium cluster-based oxides and oxychlorides are reported. The Nb6 metal cluster is edge-bridged by twelve inner ligands and additionally bonded to six apical ligands to form Nb6Li12La6 units (L = Cl, O) wherein oxygen and chlorine are perfectly ordered. Oxygen favours the interconnection of clusters via double Oi–a/Oa–i bridges in a similar way to the double Si–a/Sa–i bridges found in Chevrel phases based on face capped Mo6Li8La6 units. Periodic density functional theory (DFT) calculations confirm that increasing the number of inner oxygen ligands at the expense of chlorine atoms favours the 14 metal-electron (ME) count per octahedral cluster unit. It is also shown that weak interactions occur between neighbouring clusters. Indeed, magnetic measurements performed on AxNb6Cl12O2 (A = Rb, x = 0.816(8) ; A = Cs, x = 1) series containing 15-ME species evidence antiferromagnetic interactions at low temperatures. Broken-symmetry DFT calculations of exchange parameters within spin dimer analysis confirm the experimental results.

Izvorni jezik
Engleski

Znanstvena područja
Fizika, Kemija

Napomena
Rad je napravljen u okviru Francsko-Hrvatskog PHC COGITO programa (2009-2010/19646UJ).

POVEZANOST RADA