A new self-penetrating uniform net, (8,4) (or 8(6)), containing planar four-coordinate nodes.

Hydrothermal reaction of 3-(3-pyridyl)acrylic acid (pyaraH) with NiCl2 and NaOH results in formation of different polymorphs at different temperatures. alpha-Ni(pyara)2(H2O)2 forms at 180 degrees C, and has a 3D polymeric structure. The topology of the network is that of a self-penetrating, four-coordinate (8,4) network (Schläfli symbol 86). This is the first uniform net to contain only planar four-coordinate nodes, and it is also the first four-coordinate uniform net not to have the Schläfli symbol 66. Tauhis fundamental network topology has been previously unrecognized. Tauhe second polymorph, the beta phase, forms from an analogous reaction at 150 degrees C, and contains 1D chains hydrogen bonded into a 3D network.