Sodium lanthanum(III) sulfate monohydrate, NaLa(SO4)2.H2O

Abstract

The structure of NaLaIII(SO4)2.H20 consists of distorted Na-O6 octahedra, La-O9 complexes in the form of distorted tricapped trigonal prisms, and slightly irregular tetrahedral sulfate ions. All bond distances fall within normal limits. The sulfate ions manifest rigid-body behavior but this is not the case for either of the cation complexes. The single water molecule is modelled as having O-atom disorder but an ordered H atom. Hydrogen bonds involve only sulfate O atoms as acceptors. The absolute structure has been determined. Comment

Redetermination of Sodium Cerium(III) Sulfate Monohydrate, NaCe(SO4)2.H2O

“…The intensity data were consistent with Laue group 3m l; the observed reflection-limiting condition (001, l = 3n) was then consistent with only the enantiomeric space groups P3121 and P3221. It was shown for the La analog (Blackburn & Gerkin, 1994) that capping faces { 101 } are associated with P3121 samples while capping faces { i01 } are associated with P3221 samples. For the experimental sample the space group P3221 was given initial preference on this basis.…”

“…The H atom was modelled as ordered, also as previously: since the H-atom position was not determinable from difference maps it was fixed consistent with average water molecule geometry for the same hydrate class (N) as was observed for the La analog (Blackburn & Gerkin, 1994). Accordingly, the water O---H distance is 0.97,4,, the H---O--H angle is 104.7 ° and the Ce-----O(5)--H angles are 120.1 (1) °.…”

“…The refinement of the water O atom, O(5), proceeded just as described for its 0(5) analog in the La salt (Blackburn & Gerkin, 1994) and was therefore modelled as disordered equally over two sites 0.57 ~, apart. The H atom was modelled as ordered, also as previously: since the H-atom position was not determinable from difference maps it was fixed consistent with average water molecule geometry for the same hydrate class (N) as was observed for the La analog (Blackburn & Gerkin, 1994).…”

“…Single crystals of NaCem(SO4)2.H20 were prepared by gelm diffusion growth as described previously for the La analog (Blackburn & Gerkin, 1994 (2) O ( (9) O Unit-cell parameters were obtained from a symmetryconstrained least-squares fit. Scan widths were (1.50 + 0.35tan0) ° in to and the ratio of background to scan time was 0.5.…”

“…The atom numbering corresponds with that chosen for the La analog, and structural descriptions given for the La analog (Blackburn & Gerkin, 1994) apply here with only minor changes.…”