title: Structures of the chain metaphosphates NaM(PO3)3 (M = Ca or Sr).
abstract: Solid-state (23)Na and (31)P magic-angle spinning nuclear magnetic resonance spectroscopy and X-ray crystallography have been used to study the structures of the chain metaphosphates NaCa(PO(3))(3) and NaSr(PO(3))(3). The compounds are isostructural and crystallise in space group P(-1) with the following parameters: NaCa(PO(3))(3), a = 6.711 A, b = 6.934 A, c = 7.619 A, alpha = 83.44 degrees , beta = 81.41 degrees , gamma = 82.80 degrees ; NaSr(PO(3))(3)a = 6.805 A, b = 7.133 A, c = 7.720 A and alpha = 83.71 degrees , beta = 80.48 degrees , gamma = 82.87 degrees . Both structures contain anionic metaphosphate chains of (PO(3))(n) (n) with ionic contacts to Na(+) ions in distorted octahedral sites and Ca(2+) (or Sr(2+)) in distorted dodecahedral sites. (31)P and (23)Na NMR are entirely consistent with the crystallographic data and an empirical method for assigning (31)P resonances to particular crystallographically unique P atoms is described.
authors.affiliation: Centre for Materials Research, School of Biological and Chemical Sciences, Queen Mary, University of London, Mile End Road London E1, 4NS, UK. i.abrahams@qmul.ac.uk
authors.forename: I
authors.initials: I
authors.lastname: Abrahams
authors.forename: G E
authors.initials: GE
authors.lastname: Hawkes
authors.forename: A
authors.initials: A
authors.lastname: Ahmed
authors.forename: T
authors.initials: T
authors.lastname: Di Cristina
authors.forename: D Z
authors.initials: DZ
authors.lastname: Demetriou
authors.forename: G I
authors.initials: GI
authors.lastname: Ivanova
mesh_terms: D002118:Calcium / Q000737:chemistry*; D018360:Crystallography, X-Ray; D009682:Magnetic Resonance Spectroscopy / Q000379:methods / Q000592:standards; D008958:Models, Molecular; D015394:Molecular Structure; D010710:Phosphates / Q000737:chemistry*; D010759:Phosphorus Isotopes; D012015:Reference Standards; D012964:Sodium / Q000737:chemistry*; D012975:Sodium Isotopes; D013055:Spectrophotometry, Infrared / Q000379:methods; D013324:Strontium / Q000737:chemistry*; D013696:Temperature
chemical_list: D010710:Phosphates; D010759:Phosphorus Isotopes; D012975:Sodium Isotopes; D012964:Sodium; D002118:Calcium; D013324:Strontium