Electron density distribution in bis(guanidinium) disodium hypodiphosphate heptahydrate, (CH₆N₃)₂Na₂(P₂O₆)·7H₂O.

X‐ray structural analysis of bis(guanidinium) disodium hypodiphosphate heptahydrate, (CH6N3)2Na2(P2O6)·7H2O revealed close Na+...guanidinium [Na...N 3.0366 (6) Å] and water...guanidinium O—H...N [H...N 2.07 Å, O...N 3.0401 (9) Å] contacts, the nature of which is explored with the use of electron density distribution and Hirshfeld surface analysis. The crystal structure is governed by coordination interactions to Na+ cations and an extensive network of hydrogen bonds, in which guanidinium cations, hypodiphosphate ions and water molecules are involved. Na+ cations are in tetragonal pyramidal or octahedral environment, which was proved by continuous shape measures. From ∇2ρ(rc) and bond degree values, the character of P—P bonds are classified as shared shell or covalent bond types, whereas P—O bonds are of transit closed shell or polarized covalent types. Despite the lack of a lone electron pair on the N atom and positive charge of the guanidinium cation, the existence of an O—H...N hydrogen bond was confirmed by electron density studies. [ABSTRACT FROM AUTHOR]