skip to main content

Title: Crystallinity and compositional changes in carbonated apatites: Evidence from {sup 31}P solid-state NMR, Raman, and AFM analysis

Solid-state (magic-angle spinning) NMR spectroscopy is a useful tool for obtaining structural information on bone organic and mineral components and synthetic model minerals at the atomic-level. Raman and {sup 31}P NMR spectral parameters were investigated in a series of synthetic B-type carbonated apatites (CAps). Inverse {sup 31}P NMR linewidth and inverse Raman PO{sub 4}{sup 3−}ν{sub 1} bandwidth were both correlated with powder XRD c-axis crystallinity over the 0.3–10.3 wt% CO{sub 3}{sup 2−} range investigated. Comparison with bone powder crystallinities showed agreement with values predicted by NMR and Raman calibration curves. Carbonate content was divided into two domains by the {sup 31}P NMR chemical shift frequency and the Raman phosphate ν{sub 1} band position. These parameters remain stable except for an abrupt transition at 6.5 wt% carbonate, a composition which corresponds to an average of one carbonate per unit cell. This near-binary distribution of spectroscopic properties was also found in AFM-measured particle sizes and Ca/P molar ratios by elemental analysis. We propose that this transition differentiates between two charge-balancing ion-loss mechanisms as measured by Ca/P ratios. These results define a criterion for spectroscopic characterization of B-type carbonate substitution in apatitic minerals. - Graphical abstract: Carbonated apatite shows an abrupt change inmore » spectral (NMR, Raman) and morphological (AFM) properties at a composition of about one carbonate substitution per unit cell. Display Omitted - Highlights: • Crystallinity (XRD), particle size (AFM) of carbonated apatites and bone mineral. • Linear relationships among crystallinity, {sup 31}P NMR and Raman inverse bandwidths. • Low and high carbonated apatites use different charge-balancing ion-loss mechanism.« less
Authors:
;  [1] ;  [1] ;  [2] ;  [3] ;  [4] ;  [1] ; ; ; ;  [5] ;  [1] ;  [4] ;  [1] ;  [2] ;  [1]
  1. Department of Chemistry, University of Michigan, Ann Arbor, MI 48109-1055 (United States)
  2. (United States)
  3. Department of Biophysics, University of Michigan, Ann Arbor, MI 48109-1055 (United States)
  4. Department of Chemistry and Science of Advanced Materials Program, Central Michigan University, Mt. Pleasant, MI 48859 (United States)
  5. School of Dentistry, University of Michigan, Ann Arbor, MI 48109-1055 (United States)
Publication Date:
OSTI Identifier:
22274123
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Solid State Chemistry; Journal Volume: 206; Other Information: Copyright (c) 2013 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; APATITES; ATOMIC FORCE MICROSCOPY; CHEMICAL SHIFT; IONS; NUCLEAR MAGNETIC RESONANCE; PARTICLE SIZE; PHOSPHATES; PHOSPHORUS 31; POWDERS; RAMAN SPECTROSCOPY; SOLIDS; X-RAY DIFFRACTION