Sodium 1‐carboxycyclopropane‐1‐carboxylate cyclopropane‐1,1‐dicarboxylic acid monohydrate

In the title type B 2 acid salt, Na( L H)( L H 2 )·H 2 O [ L H 2 = C 2 H 4 C(CO 2 H) 2 ] or Na + ·C 5 H 5 O 4 − ·C 5 H 6 O 4 ·H 2 O, the vertices of a distorted octahedron centred on each Na + cation are defined by six O atoms, one from a water molecule, one from an internally hydrogen‐bonded L H − anion and four from three neutral L H 2 acid molecules. Chains of edge‐sharing O 6 octahedra are stabilized by hydrogen bonds, which interconnect the donor H 2 O and L H 2 molecules and L H − anions. In particular, the L H 2 molecule donates H atoms to L H − and H 2 O and forgoes the internal hydrogen bond which stabilizes the free acid and all of its characterized salts.