title: The triclinic form of dipotassium cobalt(II) bis-(dihydrogendiphosphate) dihydrate.
abstract: In the title compound, K(2)Co(H(2)P(2)O(7))(2)·2H(2)O, the octa-hedrally coordinated Co(2+) ion lies on an inversion centre. Two bidentate dihydrogendiphosphate anions form the equatorial plane of the [CoO(6)] octa-hedron which is completed by two water mol-ecules in axial positions. This results in isolated {Co(H(2)O)(2)[H(2)P(2)O(7)](2)}(4-) entities linked into a three-dimensional network through K-O bonds and O-H⋯O hydrogen-bonding inter-actions involving the dihydrogendiphosphate anions and water mol-ecules. The dihydrogendiphosphate anion, (H(2)P(2)O(7))(2-), is bent and shows an almost eclipsed conformation.
authors.forename: Abdellatif
authors.initials: A
authors.lastname: Lamhamdi
authors.forename: Rachid
authors.initials: R
authors.lastname: Essehli
authors.forename: Brahim
authors.initials: B
authors.lastname: El Bali
authors.forename: Michal
authors.initials: M
authors.lastname: Dušek
authors.forename: Karla
authors.initials: K
authors.lastname: Fejfarová