Journal of Solid State Chemistry 178 (2005) 1738–1752 Hydrothermal synthesis and structure of organically templated chain, layered and framework scandium phosphates Stuart R. Miller, Alexandra M.Z. Slawin, Philip Wormald, Paul A. Wright à School of Chemistry, The University of St. Andrews, Purdie Building, North Haugh, St. Andrews, Fife KY16 9ST, UK Received 27 January 2005; received in revised form 8 March 2005; accepted 8 March 2005 Available online 25 April 2005 Abstract 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, 31 P and 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 3 NC 2 H 4 NH 3 ) 3 ][Sc 3 (OH) 2 (PO 4 ) 2 (HPO 4 ) 3 (H 2 PO 4 )], P ¯ 1, a ¼ 5:4334ð6Þ, b ¼ 8:5731ð9Þ, c ¼ 16:3022ð18Þ ( A, a ¼ 79:732ð4Þ, b ¼ 83:544ð4Þ, g ¼ 80:891ð5Þ1, Z ¼ 2, is built up of scandium phosphate ribbons, based on trimers of ScO 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 3 NC 4 H 8 NH 3 ) 3 ][(Sc(OH 2 )) 6 Sc 2 (HPO 4 ) 12 (PO 4 ) 2 ], P ¯ 3, a ¼ 13:8724ð3Þ, c ¼ 9:4351ð11Þ ( A, Z ¼ 1, and 3, [(H 3 NC 4 H 8 NH 3 ) 2 (H 3 O)][Sc 5 F 4 (HPO 4 ) 8 ], C2=m, a ¼ 12:8538ð4Þ, b ¼ 14:9106ð4Þ, c ¼ 10:1906ð3Þ ( A, b ¼ 101:17ð9Þ1, Z ¼ 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 6 octahedra are linked by three vertices of hydrogenphosphate groups into sheets and the sheets pillared by ScO 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 6 octahedra and tetrameric arrangements of ScO 4 F 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 3 + groups fitting into recesses in the layers. Compound 4, [(C 6 H 11 NH 3 )][ScF(HPO 4 )(H 2 PO 4 )], Pbca, a ¼ 7:650ð3Þ, b ¼ 12:867ð5Þ, c ¼ 26:339ð11Þ ( A, Z ¼ 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 4 F 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. r 2005 Elsevier Inc. All rights reserved. Keywords: Hydrothermal crystallisation; Scandium phosphates; Organic templates; Solid-state NMR 1. Introduction Since the discovery of aluminophosphate molecular sieves consisting primarily of tetrahedrally linked frame- works [1], metal phosphates have been synthesised hydrothermally with increasing diversity, in terms of both their chemical composition and structural motifs [2]. In particular, families of gallium [3–6], iron(III) [7] and indium [8] phosphates and fluorophosphates have been reported. Scandium is among the metals most recently investigated as a structural element of open ARTICLE IN PRESS www.elsevier.com/locate/jssc 0022-4596/$-see front matter r 2005 Elsevier Inc. All rights reserved. doi:10.1016/j.jssc.2005.03.012 à Corresponding author. Fax: +441334463808. E-mail address: paw2@st-andrews.ac.uk (P.A. Wright).