Quantification of crystalline phases and measurement of phosphate chain lengths in a mixed phase sample by P-31 refocused INADEQUATE MAS NMR

O'Dell LA; Guerry P; Wong A; Abou Neel EA; Pham TN; Knowles JC; Brown SP; Smith ME

Chemical Physics Letters, Vol.455, No.4-6, 178-183, 2008

DOI10.1016/j.cplett.2008.02.070 Export Citation

Quantification of crystalline phases and measurement of phosphate chain lengths in a mixed phase sample by P-31 refocused INADEQUATE MAS NMR

O'Dell LA, Guerry P, Wong A, Abou Neel EA, Pham TN, Knowles JC, Brown SP, Smith ME

A P-31 refocused INADEQUATE pulse sequence has been used in combination with XRD to identify and quantify the crystalline phases present in a ternary sodium calcium phosphate ceramic of composition (CaO)(0.4)(Na2O)(0.1)(P2O5)(0.5). Both the NMR and XRD identified the two main phases present as NaCa(PO3)(3) and beta-Ca(PO3)(2). A third unidentified calcium phosphate phase was also observed by MAS NMR, featuring a chain of six crystallographically distinct PO4 units, the P-31 MAS NMR chemical shifts of which have been identified in the correct sequence along the chain. (C) 2008 Elsevier B.V. All rights reserved.