Your videos are becoming better and better and looking extremely nice. I love watching your channel evolve and grow. Great video, by the way! I thoroughly enjoyed it and it was very informative. Thank you for posting it!

Excellent video and crystals, my favorite copper complex! The complex is only stable when there's enough ammonia present surrounding it to maintain its structure as the crystal ammonia leaves over time, similar to how some compounds lose crystal water over time, so if you keep those crystals completely dry and without an ammonia atmosphere they will slowly decompose as they off-gas ammonia over time. I store my large 100g sample in a about 20mL of 30% NH4OH solution, and my small 5g sample of crystals much like yours just wet with a few mL of 30% NH4OH solution, and they've kept without decomposition through -10 to 40C storage temps for over a year. By the way, you can grow very large crystals by doing a recrystallization from hot ammonia water solution. You can use some ethanol to alter the polarity of the ammonia solution but this reduces crystal size as it hastens crystal formation, so it's better to just use heat and only add as much ammonia water as is needed to fully dissolve the material. Additionally, 10-15% NH4OH works better than concentrated or very diluted stuff. Once fully dissolved cool slowly and gradually by transferring vessel to a water bath at about 20C lower than your dissolution temp. Allow it to sit at least four hours then reduce the bath temp gradually until at RT. When I did mine I just adjusted the temp twice a day since I wasn't in a rush, got giant crystals over a cm in diameter.

That was the first reaction I ever did, cool

You can grow much larger crystals and more easily when you just overlay the ethanol onto the TAC-solution with a measuring pipette and let it stand for a few days at RT. The crystals will grow from the contact surface of both fluids (of different densities) into the buttom layer with the solution. It's best to use a cylinder or a bigger testtube for that, which can be stoppered meanwhile. I am planning to make a video about that sometime.

Loved the video and your efforts

I had studied deep blue colour in inorganic chemistry but this is too good

I tried making this a time or two when I had copper solutions, but my ammonia water was not very concentrated. I need to make some just had issues with suckback before and it was a hastle. I love the rich cobalt-blue color, though.

Very nice! If you want to see how to grow really nice crystals of this, look on ScienceMadness for the thread titled **"Has anyone grown nice crystals of tetraamminecopper(II) sulfate?"**

Sir you did great and I have one doubt? , Can you please tell how to make 25% of w/w ammonia solution

Would this as easily form a large mono crystal if you suspended one on a string and suspended it in a solution with the rest disolved, like you can do with the sulfate?

The nitrate salt of this is a really pretty color too. Unfortunately it doesn't translate well on video.

How about trans Tetraammine dichloro cobalt (iii)? If I recall it’s prepared by reacting Tetraammine carbonato cobalt (iii) with HCl with slight heating.

Thankyou Sir💕

How much temperature will be of the water bath at that time?

You could not get a clear solution on heating on waterbath because you were taking out the conical flask out of warm water bath frequently. This results in lowering of temperature of complex solution forcing the simultaneous reprecipitation....

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