From single-molecule magnetism to long-range ferromagnetism in Hpyr[Fe(17)O(16)(OH)(12)(py)(12)Br(4)]Br(4) by Vecchini, C, Ryan, D, Cranswick, L, Evangelisti, M, Kockelmann, W, Radaelli, P, Candini, A, Affronte, M, Gass, I, Brechin, E, Moze, O