Caesium propano-ate monohydrate.

Caesium propano-ate monohydrate, Cs ⁺ ·C ₃ H ₅ O ₂ ^- ·H ₂ O, is composed of two symmetry-independent Cs ⁺ cations, which are situated on the special position 4 e of space group P 2 ₁ m , one symmetry-independent propano-ate mol-ecule in a general position and a pair of water mol-ecules also situated on special position 4 e . Two pairs of these symmetry-independent cations, four propano-ate mol-ecules and two pairs of symmetry-independent water mol-ecules form a repeat unit. These units form columns that are directed along the c axis and possess symmetry mm 2. There are four such columns passing through each unit cell. Each column is inter-connected to its neighbours by four bifurcated three-centred O _w -H⋯O _p (w = water, p = propano-ate) hydrogen bonds of moderate strength. There are also four intra-molecular O _w -H⋯O _p hydrogen bonds of moderate strength within each column. One Cs ⁺ cation is coordinated by six oxygen atoms (two water and four carboxyl-ate) in a trigonal-prismatic geometry, while the other Cs ⁺ cation is coordinated by four water and four carboxyl-ate O atoms in a tetra-gonal-prismatic arrangement.
(© Samolová and Fábry 2020.)