Biomedical Engineering Reference
In-Depth Information
1883 [72]. Chemical formulae of DCP (as “Mono-Hydrogen Calcium
Orthophosphate, HCaPO
”) and MCP (as “Tetra-Hydrogen Calcium
4
Phosphate, H
”) have been known since, at least, 1879
[43, pp. 205-206]. Interestingly that in a publication of 1871, the
chemical formulae of calcium orthophosphates were written in
different ways: 3CaO PO
Ca(PO
)
4
4
2
for apatite and CaO 2HO PO
for “some acid
5
5
phosphate of lime” [46].
Neutral phosphates of lime have been known since, at least, 1872
[73]. Besides, in the 19
th
century, calcium apatites were considered
as combined compounds, which results from this citation: “Calcium
phosphate, combined with calcium chloride or calcium fluoride,
occurs in the well-known minerals, apatite and osteolite.” [43, p. 188].
One might guess that, in the 19
century, the atomic arrangement
of single molecule of carbonateapatite (Fig. 8.1) could have inspired
researchers to compose similar drawings for the single molecules of
FA, HA and/or chlorapatite; however, I have not succeeded to find
anything on this matter.
Chemical equations, describing various interactions between
calcium phosphates and other chemicals have been known since, at
least, 1863. For example, the afore-cited production processes of both
orthophosphoric acid and white phosphorus from the Lavoisier book
[17], in 1863 were written using chemical equations [68]: “When
bone-phosphate is digested in dilute sulphuric acid, it is resolved
into sulphate of lime and (if a sufficiency of sulphuric acid be used)
phosphoric acid: 3(CaO),PO
th
.” (p. 331).
Furthermore, various types of phosphates (namely, metaphosphate,
acid phosphate) and differences in their solubility have been already
known. Let me cite: “In order to prepare phosphorus, the bone-ash
is first mixed with so much dilute sulphuric acid as to form the acid
phosphate:
+ 3SO
= 3[CaO,SO
] + PO
5
3
3
5
.
The solution of this soluble acid phosphate is next poured of
from the precipitated gypsum, and evaporated to dryness, after
which, the solid residue being heated to redness, water is given off
and calcium metaphosphate formed:
Ca
(PO
)
+ 2H
SO
= CaH
(PO
)
+ 2CaSO
3
4
2
2
4
4
4
2
4
O.
This salt is then carefully mixed with charcoal, and heated to
bright redness in earthenware retorts shown in Fig. 147, when the
following change takes place:
CaH
(PO
)
= Ca (PO
)
+ 2H
4
4
2
3
2
2
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