“…On the whole, it appears that only long-range superexchange occurs in this compound. Actually, the magnitude of the Fe}O}P}O}Fe interaction is an open question, as NeH el temperatures of 29 and 47 K have been reported in NaFeP O (13) and Na Fe (PO ) (14), respectively, and only 4 K in KBaFe (PO ) (15). Moreover, here we have both Fe}O}P}O}Fe and Fe}O}P}O}P}O}Fe interactions and it is clear that we have to consider two types of interactions, intra-and interlayers, from the strongest to the weakest.…”