FMF - Friends of Minerals Forum, discussion and message board

[Parvin]

Hi.
Does anyone know how to make fluorescent FLUORAPATITE ?
I have found the patent using tetracalcium phospate, but I am not interested going that way, I am looking for a simple way.
Thank you.

[newryqs]

See Jaffe (1951) Abstract on the Literature on Synthesis of Apatites and Some Related Phosphates. USGS Circular 135. It's the first hit on google when you search apatite synthesis. You didn't say what color you wanted the apatite to fluoresce. As I remember, adding a Mn2+ compound, you should be able to get an orange-yellow in LW. Amounts greater than 4% MnO do not generally yeild fluorescent apatites. Putting uranium into the mixture will give you something other than an apatite structure as U is not particularly acceptable in apatite structures.

The resultant synthetic will likely be a fine-grained precipitate, unless you have the technical synthesis equipment for high-temperatures. You can apparently synthesize apatites at 25 degrees C.

Best Wishes, Van

[Parvin]

Hi.
I am not intending using any Mn to make the sample fluorescent.

I am thinking to use Calcium Hydroxide+Phosphoric Acid, and then doping with Fluoride salt.

Any idea???
Does anybody knows how the process should be in details? I am a little bit confused with concentration of each components....

Thanks.

[newryqs]

I presume that the "fluoride salt" contains an activator. As fluorapatite is what you are making, the fluoride salt would only assure that you had full F in the apatite. Does ultra-pure fluorapatite fluoresce without an activator?

[Parvin]

I have no idea if the pure fluoroapetite is fluorescent or no. I have tried to make some, doesn't show any fluorescent activity. Any idea? Thank you.

[newryqs]

The first question is, "Did you actually make fluorapatite?" I don't think pure fluorapatite is fluorescent. I presume you have excellent chemical skills and you controlled temperature, used pure reagents, had appropriate concentrations, etc. The next step would be to add some Mn2+ to the mix and observe. Remember that >4 mole percent MnO quenches fluorescence. You might try adding Eu and other elements.

[Parvin]

To be honest, I am not sure if the what I have got is Fluoroapetite....
Do you have any idea in order to synthesis fluopapetite in a simple way.. Thanks.

[newryqs]

The concern is always present that even if you "follow the directions" exactly, the result may be different or a mixture. It is likely that you have a fine-grained precipitate and the identification options are limited. You could do a quantitative chemical analysis or you could x-ray the product you actually made. As a precipitate, you wouldn't be able to measure refractive index or density, but you might use a biological microscope to see if all of the crystallites had a similar appearance and perhaps a characteristic appearance. Fluoapatite occurs over a wide range of conditions and one would expect that there would not be any difficulty making it. In the eighteenth century, when Antoine Lavoisier applied for membership in the French Academy, the members gathered in Lavoisier's lab, but his marvelous experiment didn't work. After the failure, Lavoisier slumped into a funk and didn't repeat the experiment to determine what went wrong, at least for quite a time later. When the experiment was re-tried, it worked perfectly. He later figured out that some stray chemical residue on his glassware had promoted the reaction. Lavoisier recalled the representatives, the experiment was a successful, he was admitted to the Academy and all was fine until the Revolution when he was one of the first up against the wall. (Lavoisier was in the nobility, and worse, he was a tax collector.) The moral of the story is don't wash your glassware OR beware of residues on your glassware as you may get unwanted results. You didn't say anything about the conditions of your synthesis, but varying temperatures could affect kinetics, solubility products, molecular stability, etc. You now need to prove to yourself that you actually made an apatite. John Attard offers an x-ray service as others do. There are labs that have electronic methods of determining chemistry, including F. You might know a friendly mineralogist. Also, you could sublimely believe that you did really make apatite and try to add a fluorescence activator to the mix. Does your synthetic have to be fluorapatite?

Best Wishes, Van

[Parvin]

Thanks Van, Yes, it has to be Fluorapetite...