Hydrothermal synthesis and structure of organically templated chain, layered and framework scandium phosphates

Journal Article · Wed Jun 15 04:00:00 EDT 2005 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2005.03.012· OSTI ID:20725958

Miller, Stuart R ^[1]; Slawin, Alexandra M.Z. ^[1]; Wormald, Philip ^[1]; Wright, Paul A ^[1]

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1. School of Chemistry, University of St. Andrews, Purdie Building, North Haugh, St. Andrews, Fife KY16 9ST (United Kingdom)

Four scandium phosphate-based structures have been prepared hydrothermally in the presence of the primary diamines ethylenediamine and diaminobutane and the primary amine cyclohexylamine and characterised by single crystal and powder X-ray diffraction, {sup 31}P and {sup 45}Sc solid-state MAS NMR and chemical analysis. Charge balancing protons in the structures are located using bond valence sum calculations and postulated hydrogen bonding networks. Compound 1, [(H{sub 3}NC{sub 2}H{sub 4}NH{sub 3}){sub 3}][Sc{sub 3}(OH){sub 2}(PO{sub 4}){sub 2}(HPO{sub 4}){sub 3}(H{sub 2}PO{sub 4})], P1-bar , a=5.4334(6), b=8.5731(9), c=16.3022(18)A, {alpha}=79.732(4), {beta}=83.544(4), {gamma}=80.891(5){sup o}, Z=2, is built up of scandium phosphate ribbons, based on trimers of ScO{sub 6} octahedra linked by OH groups. These trimers are joined through phosphate groups bound through three oxygens, and are decorated by phosphate groups linked by a single oxygen atom. The ribbons are arranged parallel to the a-axis and linked one to another by fully protonated ethylenediammonium ions. Compounds 2, [(H{sub 3}NC{sub 4}H{sub 8}NH{sub 3}){sub 3}][(Sc(OH{sub 2})){sub 6}Sc{sub 2}(HPO{sub 4}){sub 12}(PO{sub 4}){sub 2}], P3-bar , a=13.8724(3), c=9.4351(11)A, Z=1, and 3, [(H{sub 3}NC{sub 4}H{sub 8}NH{sub 3}){sub 2}(H{sub 3}O)][Sc{sub 5}F{sub 4}(HPO{sub 4}){sub 8}], C2/m, a=12.8538(4), b=14.9106(4), c=10.1906(3)A, {beta}=101.17(9){sup o}, Z=2, were prepared using diaminobutane as the organic template in the absence and presence, respectively, of fluoride ions in the gel. Compound 2 has a pillared layered structure, in which ScO{sub 6} octahedra are linked by three vertices of hydrogenphosphate groups into sheets and the sheets pillared by ScO{sub 6} octahedra to give a three-dimensionally connected framework isostructural with a previously reported iron(III) hydrogenphosphate. The protonated diaminobutane molecules occupy cavities between the layers. Compound 3 has a layered structure in which isolated ScO{sub 6} octahedra and tetrameric arrangements of ScO{sub 4}F{sub 2} octahedra, the latter linked in squares through fluoride ions, are connected by phosphate tetrahedra that share two or three oxygens with scandium atoms. In this structure, the protonated diaminobutane molecules connect the layers, the -NH{sub 3}{sup +} groups fitting into recesses in the layers. Compound 4, [(C{sub 6}H{sub 11}NH{sub 3})][ScF(HPO{sub 4})(H{sub 2}PO{sub 4})], Pbca, a=7.650(3), b=12.867(5), c=26.339(11)A, Z=8, the first scandium phosphate to be prepared with a monoamine, is also a layered solid. In this case, the layers contain single chains of ScO{sub 4}F{sub 2} octahedra which share fluoride ions in trans positions. Phosphate tetrahedra bridge across scandiums via two of their four oxygens, both within the same chain and also to neighbouring chains to make up the layer. The protonated amine groups of the cyclohexylamine molecules achieve close contact with phosphates of the layer, while the cyclohexyl moieties, which are in the chair configuration, project into the interlayer space.

• OSTI ID: 20725958
• Journal Information: Journal of Solid State Chemistry, Journal Name: Journal of Solid State Chemistry Journal Issue: 6 Vol. 178; ISSN 0022-4596; ISSN JSSCBI
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
CHEMICAL ANALYSIS
CRYSTALLIZATION
FLUORINE IONS
HYDROTHERMAL SYNTHESIS
IRON PHOSPHATES
LAYERS
MONOCLINIC LATTICES
MONOCRYSTALS
NUCLEAR MAGNETIC RESONANCE
ORTHORHOMBIC LATTICES
SCANDIUM PHOSPHATES
TRICLINIC LATTICES
TRIGONAL LATTICES
X-RAY DIFFRACTION