Jörgen Albertsson

Inorganic ion exchangers—VII: The sorption of first-row transition metal ions on a zirconium phosphate gel of low crystallinity, and a study of the reproducibility of the gel

Abstract Zirconium phosphate gels of low crystallinity have been prepared and characterized by their X-ray diffractograms, and by their dehydration, phosphate release and neutralization curves. At low pH, the phosphate release is not primarily due to any hydrolysis but rather to washing out phosphoric acid which adheres very stubbornly to the gel. It has been confirmed that the affinity for Cs+ increases strongly when the gels are dehydrated to ∼-1 mole H2O/mole Ze, and it has further been found that a similar increase of affinity, though less marked, occurs also for Na+. The sorption of the first-row transition metal ions Cr3+, Fe3+; Co2+, Ni2+, Cu2+, Zn2+ has been investigated. The divalent ions are all sorbed to about the same extent, and their affinity is not very different from that of Sr2+. Of the trivalent ions, Cr3+ is sorbed a little more strongly than the divalent ions, while the affinity for Fe3+ is extremely high. The uptake of this ion is not a simple exchange reaction but rather a process involving the introduction of Fe(III) into the matrix of the exchanger.

X-ray crystal structure of galabiose, O-α-d-galactopyranosyl-(1→4)-d-galactopyranose

Abstract O -α- d -Galactopyranosyl-(1→4)- d -galactopyranose, C 12 H 22 O 11 , M r = 342.30, crystallises in the orthorhombic space group P 2 1 2 1 2 1 , and has a = 5.826(1), b = 13.904(3), c = 17.772(4) A, Z = 4, and D x = 1.579 g.cm −3 . Intensity data were collected with a CAD4 diffractometer. The structure was solved by direct methods and refined to R = 0.063 and R w = 0.084 for 2758 independent reflections. The glycosidic linkage is of the type 1-axial-4-axial with torsion angles φ O-5′ (O-5′C-1′O-1′C-4) = 98.1(2)°, ψ C-3 (C-3C-4O-1′C-1′) = −81.9(3)°, φ H (H-1′C-1′O-1′C-4) = −18°, and ψ H (H-4C-4O-1′C-1′) = 35°. The conformation is stabilised by an O-3 · · · O-5′ intramolecular hydrogen-bond with length 2.787(3) A and O-3H · · · O-5′ = 162°. The glycosidic linkage causes a folding of the molecule with an angle of 117° between the least-square planes through th pyranosidic rings. The crystal investigated contained 56(1)% of α- and 44(1)% of β-galabiose as well as ∼70% of the gauche-trans and ∼30% of the trans-gauche conformers about the exocyclic C-5′C-6′ and C-5C-6 bonds. The crystal packing is governed by hydrogen bonding that engages all oxygen atoms except the intramolecular acceptor O-5′ and the glycosidic O-1′ oxygen atoms.

Lead(II) oxydiacetate hydrate

The coordination polyhedron around the Pb atom in the title compound, poly[aqualead(II)-mu(5)-oxydiacetato], [Pb(mu(5)-C4H4O5)(H2O)](n), is a distorted square antiprism formed by three O atoms from one oxydiacetate ligand, four O atoms from four other identical ligands and one water O atom, resulting in a three-dimensional network structure. The almost planar oxydiacetate ligand is disordered over two positions. The Pb lone-pair 6s(2) electrons show stereochemical activity in the coordination sphere.