Structures of the chain metaphosphates NaM(PO3)3 (M = Ca or Sr)

• Published in: Magnetic resonance in chemistry 2008-04, Vol.46 (4), p.316-322
• Main Authors: Abrahams, I., Hawkes, G. E., Ahmed, A., Di Cristina, T., Demetriou, D. Z., Ivanova, G. I.
• Format: Article
• Language: English
• Subjects: 23Na solid-state NMR; 31P solid-state NMR; Calcium - chemistry; Crystallography, X-Ray; Magnetic Resonance Spectroscopy - methods; Magnetic Resonance Spectroscopy - standards; metaphosphate; Models, Molecular; Molecular Structure; Phosphates - chemistry; Phosphorus Isotopes; Reference Standards; Sodium - chemistry; sodium calcium phosphate; Sodium Isotopes; sodium strontium phosphate; Spectrophotometry, Infrared - methods; Strontium - chemistry; Temperature; X-ray crystallography
• ISSN: 0749-1581; 1097-458X
• DOI: 10.1002/mrc.2161

Solid‐state 23Na and 31P magic‐angle spinning nuclear magnetic resonance spectroscopy and X‐ray crystallography have been used to study the structures of the chain metaphosphates NaCa(PO3)3 and NaSr(PO3)3. The compounds are isostructural and crystallise in space group P−1 with the following parameters: NaCa(PO3)3, a = 6.711 Å, b = 6.934 Å, c = 7.619 Å, α = 83.44° , β = 81.41° , γ = 82.80° ; NaSr(PO3)3a = 6.805 Å, b = 7.133 Å, c = 7.720 Å and α = 83.71° , β = 80.48° , γ = 82.87° . Both structures contain anionic metaphosphate chains of (PO3)nn with ionic contacts to Na+ ions in distorted octahedral sites and Ca2+ (or Sr2+) in distorted dodecahedral sites. 31P and 23Na NMR are entirely consistent with the crystallographic data and an empirical method for assigning 31P resonances to particular crystallographically unique P atoms is described. Copyright © 2008 John Wiley & Sons, Ltd.