 | Acta Crystallographica Section B Acta Crystallographica Section B STRUCTURAL SCIENCE, CRYSTAL ENGINEERING AND MATERIALS |
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![[Figure 1]](bm5088fig1mag.jpg)
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Figure 1
Illustration of the Ca4 and P1O4 atomic arrangement in (a) the stoichiometric β-TCP crystal model (Dickens et al., 1974  ) and (b) a hydrogen-substituted β-TCP model where some of the P1O4 tetrahedra are inverted and protonated. Representative XRD patterns of β-TCP platelets fitted by Rietveld refinement with (c) the stoichiometric and (d) the hydrogen-substituted crystal model. (Monetite and chlorapatite fractions were negligible in this sample and were not refined for the purpose of this illustration.) The difference (green line) between the observed (black) and calculated (red) intensity, characterized by χ2 values, was larger for the stoichiometric compared with the hydrogen-substituted model. EDD maps between the observed structure and (e) the structure calculated with the stoichiometric model indicated sub-occupied O2, P1 and Ca4 sites along with a positive region immediately below the P1 site, while (f) using the hydrogen-substituted model resulted in much smaller EDDs. |
![[Figure 1]](bm5088fig1.jpg)
| STRUCTURAL SCIENCE CRYSTAL ENGINEERING MATERIALS |
ISSN: 2052-5206
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