Syntheses and Crystal Structures of Two New Open‐Framework Tin(II) Phosphates: Sn 5 O 2 (PO 4 ) 2 and Sn 4 O(PO 4 ) 2

Two new three‐dimensional neutral open‐framework tin(II) phosphates, Sn 5 O 2 (PO 4 ) 2 and Sn 4 O(PO 4 ) 2 , were synthesized under hydrothermal conditions with different ratio of tin(II) oxalate, phosphoric acid and 4,4′‐diaminodiphenylmethane. Their crystal structures have been solved by single‐crystal X‐ray diffraction methods. Sn 5 O 2 (PO 4 ) 2 crystallizes in the space group $P{\bar 1}$ and contains six‐membered ring and twelve‐membered ring channels running parallel to the b axis. Sn 4 O(PO 4 ) 2 crystallizes in the space group P 2 1 / n and contains intersecting eight‐membered ring channels. These two compounds have rare trigonal‐planar Sn 3 O.