Synthesis and Structure of the First Three‐legged Low‐dimensional Iron Phosphate, [H 3 N(CH 2 ) 3 NH 2 (CH 2 ) 2 NH 2 (CH 2 ) 3 NH 3 ][Fe 3 F 6 (HPO 4 ) 2 (PO 4 )]·3H 2 O

A hydrothermal reaction of iron acetylacetonate, phosphoric acid, HF, N, N′‐bis(3‐aminopropyl)ethylenediamine and water at 150 °C gave rise to a new iron phosphate, [H 3 N(CH 2 ) 3 NH 2 (CH 2 ) 2 NH 2 (CH 2 ) 3 NH 3 ][Fe 3 F 6 (HPO 4 ) 2 (PO 4 )] · 3H 2 O ( I ). The structure consists of Fe(1)O 4 F 2 , Fe(2)O 3 F 3 octahedral and P(1)O 3 (OH) and P(2)O 4 tetrahedral building units connected through their vertices to form fragments of tancoite‐type units. The tancoite‐type units are linked through the phosphate tetrahedra forming an unusual iron phosphate with a hitherto unknown low‐dimensional structure with three‐iron center.Magnetic studies indicate a complex behavior at low temperature and the high‐temperature data (150 — 300 K) has a Curie‐Weiss behavior. The calculated room temperature magnetic moment is 6 μ B per Fe atom, and the Neel temperature, T N = 46K. Crystal data: orthorhombic, space group = I2 1 2 1 2 1 (no. 24), a = 9.9042(11), b = 12.8865(14), c = 19.783(2)Å, U = 2524.9(5), Z = 4.