In cocrystal formation what would the possible reason be for the precipitation of an amorphus oily precipitate not suitable for PXRD? Solvent was DMF and the reagent were L-thyroxine and isonicotinamide

I had the same problem of not being able to form cocrystals with other combinations with L-thyroxine and at this point i dont know what im doing wrong. The other used solvents were water and methanol and the other reagents were all organic like 3-hidroxyipiride and nikotiamide for an example. Pls help

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    $\begingroup$ For readers: PXRD stands for Powder X-Ray Diffraction (also seen as PXD) // For Luka: It is a good habit to explain in text less used acronyms. Valuable answers may be provided even by those not familiar with them. It is not very considerate to make multiple readers to google it if you can explain it in a single action. Overall, the question is written in a way like if you were catching a bus. Low effort in question formulation seldom attracts good answers. $\endgroup$
    – Poutnik
    Commented Sep 6, 2023 at 7:45

1 Answer 1


Not obtaining crystals is the typical result. Even if you have published results describing how someone else made crystals, not obtaining crystals the first time you try is the typical result. There are a lot of parameters, and you don’t have full control over them.

This is not a problem you can solve remotely. If you can talk to a local expert, your chances of obtaining crystals increase.

Some crystals rely on a badly designed incubator, some allegedly rely on smoking a certain brand of cigarettes, and some rely on letting the samples age so that they decompose slightly, but not too much.


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