K10[Co4(H2O)2(B-α-SiW9O34H)2] · 21H2O: A sandwich polyoxometalate based on the magnetically interesting element cobalt

Abstract The magnetism of a sandwich tetracobalt(II) substituted tungstosilicate K 10 [Co 4 (H 2 O) 2 (B-α-SiW 9 O 34 H) 2 ] · 21H 2 O has been studied based on an isotropic Heisenberg model supplemented by a zero-field splitting term.