Biomedical Engineering Reference
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to be the excrements of fossil reptiles, also abound in phosphate of
lime.” (p. 332) means that already in 1863 researchers were aware
on this fact.
Furthermore, let me make a citation from a publication by Wells
of 1906 [69]: “The apparent constancy of the proportion of carbonate
and phosphate of calcium in bones made an impression on Hoppe-
Seyler in I862, and we find him speculating on the possibility of
the components of the two salts being joined together to form one
giant molecule: 3 (Ca
, which he imagined might be
united in some such way” (p. 522) as shown in Fig. 8.1. Further, Wells
mentions: “This formula is interesting chiefly from the historical
standpoint, but it serves to emphasize the tendency of these salts
to appear in nearly constant proportions in the animal body, a
fact possibly of some importance.” (p. 523). Obviously, the atomic
arrangement shown in Fig. 8.1 represents the earliest structural
drawing of a single molecule of carbonateapatite. An attentive reader
will notice two different types of calcium (currently known as Ca(1)
and Ca(2)) in that structure.
(Po
)
)-CaCo
3
4
2
3
Figure 8.1
The first available structure of a bone mineral (carbonatea-
patite). Reprinted from Ref. [69].
Vitrification properties of some forms of calcium orthophosphates
at heating have been known since, at least, 1877 [70]. The modern
chemical formula of perfectly transparent crystals of natural FA as
Ca
F has been known since, at least, 1873 [71], while the major
crystallographic faces of a natural calcium apatite were described in
(PO
)
5
4
3
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