Can I grow chlorapatite crystals, $\ce{Ca10(PO4)6(Cl)2}$, at home?

Is it as simple as ordering the elements online and throwing them into a beaker, and warming it up maybe?

  • $\begingroup$ I don't think you can buy the elements online, unless you happen to be in a lab at some reputable institution. Anyway, simply mixing the constituent elements wouldn't work at all. $\endgroup$ – orthocresol Sep 13 '16 at 6:54
  • $\begingroup$ Calcium is a food supplement. Chlorine is a pool chemical. And Phosphate is a fertilizer. I looked up how minerals form and it looks like they form by cooling down/evaporating... $\endgroup$ – eromod Sep 13 '16 at 7:04
  • $\begingroup$ why wont it work? $\endgroup$ – eromod Sep 13 '16 at 7:23
  • $\begingroup$ im totally clueless atm, any hint would be nice $\endgroup$ – eromod Sep 13 '16 at 7:32
  • 3
    $\begingroup$ Calcium may be a food supplement, but that does not mean you can buy elemental calcium (or, God forbid, add it to your food). There are more obstacles with other elements. Oxygen is a gas, so you can't simply throw it into a beaker. Ditto for chlorine, which is also pretty toxic. No, chemistry totally doesn't work like that. $\endgroup$ – Ivan Neretin Sep 13 '16 at 7:35

It might be a lot harder than you think it is, because essentially every other element will influence crystal grow and purity. I found an interesting article by Esther García-Tuñón et. al., which is public access, outlining one of the possible routes to go. There might be more, but I am only using this as an illustrative example.

Here is the experimental procedure (shportened):

$\ce{CaCl2}$ [...] and β-TCP [$\ce{β-Ca3(PO4)2}$, [...]] powders were mechanically blended in different proportions in an agate mortar [...] for 12 min. Prior to mixing the $\ce{CaCl2}$ flux was dehydrated at 110 °C for 2 weeks. Thermo-gravimetric analysis [...] of the dehydrated flux showed that the remaining $\ce{H2O}$ percentage was 8wt.% and water is fully eliminated at 300 °C. After milling, the mixtures were uniaxially pressed at 60 MPa into cylindrical pellets (2.54 cm diameter) using a stainless steel dye. Five pellets (~12–15 g per batch) were placed inside a Platinum crucible and the growth process took place in a rapid melting furnace [...] at 1,100 °C for times ranging between 15 and 240 min. The heating rate was 10 °C min-1, and the cooling rates varied between 1 °C min-1 and quenching in air. [...] After cooling, the sample was washed, by rinsing in deionized water to dissolve the leftover flux. The crystals were vacuum-filtered and washing was repeated three times. Subsequently they were sieved trough a 63 μm mesh, and dried at 110 °C for 20 h.

As you see, the procedure requires high temperatures and pressures. If there was an do-it-at-home method I would assume they would have gone for that instead.

The reasons for that can be found in the discussion section.

Three different mixtures of CaCl2 and β-TCP (Fig. 1) were used to synthesize ClAp crystals. This system was selected to avoid the presence of additional species that could get incorporated into the ClAp structure, such as potassium or carbonates from the flux or the starting reagents [...].

Reference: Esther García-Tuñón, Ramiro Couceiro, Jaime Franco, Eduardo Saiz, and Francisco Guitián, Author manuscript, available in PMC 2013 Oct 1. PMCID: PMC3638812
Published in final edited form as: J Mater Sci Mater Med. 2012, 23(10), 2471–2482.

Another possibility is the following paper, to which I do not have access. Here is the abstract in full:

The first hydrothermal growth of single crystals of chlorapatite is reported. Crystals grown from the system chlorapatite-HCl-H2O at 50 000 psi and pH = 1 with the growth zone at 465 °C and dissolution zone at 360 °C are found to be of high stoichiometry.

This seems also quite extreme to me.

Reference: A. Roufosse, M.L. Harvill, O.R. Gilliam, E. Kostiner, J. of Crystal Growth 1973, 19(3), 211-212.


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