question about crystal formation of a solution

[Bisy]

so if you have multiple solutes, each having a different crystal structure but disolved together, (lets assume, for the sake of what im trying to understand, that saturation concentration is equal among the solutes) how will they behave during precipitation? will they collect with their own, and precip seperately? will they become a compound with a new crystal structure alltogether? will they interfere with eachothers ability to coalesce? etc..

 

[downwardsfromzero]

It really depends on the exact substances in question. Some compounds might co-crystallise, although this is fairly unusual. What would be the exact scenario that you envisage applying this question to?

What do you understand by "saturation concentration is equal among the solutes"? What measure of concentration would that refer to? There's a big difference between % w/v and molar concentration.

What would be causing the solutes to precipitate? Evaporation of the solvent? Temperature decrease? The saturation concentration will not vary with temperature in the same way for different compounds.

In practice, evaporating down a complex mixed solution will tend to result in tar or resin rather than crystals.

 

[Bisy]

i suspected the answer would be much more complex than the question could request. there is no particular substance in question, i was just curious about the behavior of dissolved solids upon crystalization. what i meant by saturation concentration was basically if they were such that if precipitated seperately and from a pure solution that they would behave the same.

but i believe your answer was adequate, what i got from it is that its much more complicated than that. im intelligent, but it has never been applied to chemistry. ill put a enough time into my own research next time so my questions arent so vague. thx.

actually, heres an example of where my thinking was..

quartz and calcite are 2 pure crystaline solids. if thye dissolved at the same rate, and with the same saturation concentration in some substance, what might result if both were disolved in a saturated state and left to precipitate, via evap for instance.

 

[Sakkadelic]

It really depends on the exact substances in question. Some compounds might co-crystallise, although this is fairly unusual. What would be the exact scenario that you envisage applying this question to?

What do you understand by "saturation concentration is equal among the solutes"? What measure of concentration would that refer to? There's a big difference between % w/v and molar concentration.

What would be causing the solutes to precipitate? Evaporation of the solvent? Temperature decrease? The saturation concentration will not vary with temperature in the same way for different compounds.

In practice, evaporating down a complex mixed solution will tend to result in tar or resin rather than crystals.

Harmalas from a rue extraction, how come the different alkaloids form one crystalline shape during manske?

 

[Sakkadelic]

so if you have multiple solutes, each having a different crystal structure but disolved together, (lets assume, for the sake of what im trying to understand, that saturation concentration is equal among the solutes) how will they behave during precipitation? will they collect with their own, and precip seperately? will they become a compound with a new crystal structure alltogether? will they interfere with eachothers ability to coalesce? etc..

Thanks for the question, i was wondering about that too the other day and i'd like to learn more about it..

 

[downwardsfromzero]

quartz and calcite are 2 pure crystaline solids. if thye dissolved at the same rate, and with the same saturation concentration in some substance, what might result if both were disolved in a saturated state and left to precipitate, via evap for instance.

Quartz is practically insoluble at normal temperatures and pressures. Dissolved under pressure in the Earth's crust it would act as an acid towards calcite. Various calcium silicates would form and carbon dioxide would be released. This would react with further calcite to produce calcium bicarbonate, dissolving it.

Harmalas from a rue extraction, how come the different alkaloids form one crystalline shape during manske?

That's a great question for here. Those molecules are all closely related so they "fit together" more easily. It's a good example of co-crystallisation, I suspect.

In an attempt to increase the concentration of a spent Manske solution I've found that once the harmala concentration starts to become more significant, the sodium chloride ceases to crystallise in cubic formations and begins to co-crystallise with the harmala alkaloids in a more needle-like form. This is a good reason to limit the salt concentration in a Manske precipitation to below that of saturation for sodium chloride.

 

[Bisy]

ive geeked out on a lot of subjects and hobbies till i understood them well enough to have a proffesional discussion and understanding of them. but never chemistry. the nexus has been a wealth of information.

i remember being overwhelmed with reading a tek because i had to stop and look up words and phrases like magnesium sulphate, and calcium cardonate or bicarbonite.

i knew i was capable of figuring out how to do the a/b extraction process, but by the time i got my hands on some bark, i added water, lye and pulled with naphtha. i was rolling around the floor laughing about ho ridiculous lifes problems are from a hyperspace perspective within 2 hours of picking up the mail. (bark)

i had never seen white dmt before, or dry powdery crystals. dmt was sometrhing i only rarely had the opportunity to endulge myself with.. then i didnt respect it and overindulged until i got the blockout before ever getting to try harmalas or changa or cappi or aya....

i did IV some fumerates though, and id say if youre confident and sure enough about your product being clean and that your fumerates have been washed well and youve been an IV junky in the past or present, then its an experience worth trying. (actually, if youre presently an iv junky, be extremely cautious because even if you think youre on top of it, youre not. i speak from experience.)

 

[Sakkadelic]

Harmalas from a rue extraction, how come the different alkaloids form one crystalline shape during manske?

That's a great question for here. Those molecules are all closely related so they "fit together" more easily. It's a good example of co-crystallisation, I suspect.

In an attempt to increase the concentration of a spent Manske solution I've found that once the harmala concentration starts to become more significant, the sodium chloride ceases to crystallise in cubic formations and begins to co-crystallise with the harmala alkaloids in a more needle-like form. This is a good reason to limit the salt concentration in a Manske precipitation to below that of saturation for sodium chloride.

Thanks for the answer and tip. Instead of concentrating the leftover i base then acidify and salt again keeping volumes minimal, i get around 5% of original yield. It's maybe not worth the trouble but I do it to get confirmation that my manske worked properly