title: An ordered low-temperature phase of barium nitroprusside trihydrate studied by neutron diffraction.
abstract: Crystals of barium pentacyanonitrosylferrate trihydrate (barium nitroprusside trihydrate), Ba[Fe(CN)(5)(NO)].3H(2)O, have been studied by neutron diffraction in order to examine the structural behaviour of the compound in the 20-120 K temperature range and to determine the structure at 105 K. The results show the existence of a new crystal phase of the compound at 80 K (with a duplicated a parameter), which still exists at 20 K. The crystal structure at 105 K shows a rearrangement of the water molecules, which results in an ordered structure with P1 symmetry. Two of the four independent nitroprusside cations are rotated by 4.5 degrees around the [100] direction.
authors.affiliation: Laboratoire Léon Brillouin, CEN Saclay, 91191 Gif sur Yvette, France.
authors.forename: G
authors.initials: G
authors.lastname: Chevrier
authors.forename: J M
authors.initials: JM
authors.lastname: Kiat
authors.forename: J
authors.initials: J
authors.lastname: Guida
authors.forename: A
authors.initials: A
authors.lastname: Navaza
mesh_terms: D017609:Barium Compounds / Q000737:chemistry*; D006860:Hydrogen Bonding; D008958:Models, Molecular; D015394:Molecular Structure; D033363:Neutron Diffraction; D009599:Nitroprusside / Q000031:analogs & derivatives*; D013696:Temperature; D014867:Water / Q000737:chemistry*
chemical_list: D017609:Barium Compounds; D014867:Water; D009599:Nitroprusside