Journal Article

The Monetite Structure Probed by Advanced Solid-State NMR Experimentation at Fast Magic-Angle Spinning

Yu, Yang, Stevensson, Baltzar, Pujari-Palmer, Michael, Guo, Hua, Edén, Mattias, Engqvist, Håkan

2019

Overview

We present a solid-state nuclear magnetic resonance (NMR) spectroscopy study of the local 31 P and 1 H environments in monetite [CaHPO 4 ; dicalcium phosphate anhydrous (DCPA)], as well as their relative spatial proximities. Each of the three 1 H NMR peaks was unambiguously assigned to its respective crystallographically unique H site of monetite, while their pairwise spatial proximities were probed by homonuclear 1 H– 1 H double quantum–single quantum NMR experimentation under fast magic-angle spinning (MAS) of 66 kHz. We also examined the relative 1 H– 31 P proximities among the inequivalent P1, P2 and H1, H2, H3 sites in monetite; the corresponding shortest internuclear 1 H– 31 P distances accorded well with those of a previous neutron diffraction study. The NMR results from the monetite phase were also contrasted with those observed from the monetite component present in a pyrophosphate-bearing calcium phosphate cement, demonstrating that while the latter represents a disordered form of monetite, it shares all essential local features of the monetite structure.

• Publisher: MDPI AG,MDPI
• Subject: bioceramics / Bone surgery / calcium phosphate cement / Calcium Phosphates - chemistry / Cement / double-quantum correlation 1H NMR / Experiments / Hydrogen Bonding / internuclear distance determination / Magnetic Resonance Spectroscopy - methods / Models, Molecular / Molecular Structure / monetite structure / NMR / Nuclear magnetic resonance / P-31{1H} HETCOR NMR / Proton Magnetic Resonance Spectroscopy - methods