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Finishing experiments with copper beta-alaninate urea adduct:

Cu(βAla)₂·xCO(NH₂)₂

Over several weeks, a large crystal almost 5cm in size was grown. It has very dark violet-blue color (Photo does not reproduce violet tint very well, I blame reddish incandescent light source). But in fact, the color is so dark that the crystal appears almost black.

The compound was prepared by dissolving copper hydroxy carbonate in beta-alanine, then adding urea to the solution. Solubility of the compound is moderate, around 10g/100ml at room temperature. However, it partially decomposes, when dissolved in pure water. Adding small amount of beta-alanine prevents decomposition.
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1/27/19
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Crystals of guanidinium ferric EDTA salt
C(NH₂)₃[Fe(edta)]
Very fragile dark ember sticks.
Have surprisingly low solubility for a guanidinium salt, below 10g per 100ml.
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Сrystals of a compound I discovered experimentally.

It was prepared by mixing warm saturated solutions of copper beta-alaninate and urea. Unknown product is less soluble than its constituents, and forms violet crystalline precipitate. Crystals on the photo were obtained by recrystallization of the original precipitate. Unlike pure copper beta-alaninate, which is extremely prone to dehydration, this urea adduct is completely stable. Apparently, it contains no water of crystallization.

Crystals have very dark, violet-blue color, characteristic for amino-complexes of Cu(II). Their shape is very distorted octahedron, with all three axes different. This suggests orthorhombic crystal system, though I am not sure.

Regarding its chemical composition, my guess is:

Cu(βAla)₂·xCO(NH₂)₂

where βAla is beta-alanine anion, C₃H₆NO₂, and CO(NH₂)₂ is urea. From the experimental stoichiometry data, x is probably 1 or 2.

Speaking of the nature of the compound, I think that it is a molecular adduct (held by hydrogen bonds) rather than a product of reaction, because it formed very quickly and in mild conditions.

Growth time of the biggest crystals is about 10 days. They grow slowly because of relatively low solubility of the compound, around 10g/100ml
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Recently I bought a jar of beta-alanine in the sport food shop, and made a few experiments with it. Here is one of them: copper salt of beta-alanine.

The compound was prepared by reacting copper hydroxycarbonate with beta-alanine in water solution. It is very well soluble in water. Solution has dark blue color characteristic for amino complexes of copper. It is much darker then coper sulfate solution, saturated solution is almost black.

I don't know the exact formula. From the common sense, I expect it to be chelate, Cu(βA)₂·xH₂O, where βA is β-alanine anion, C₃H₆NO₂.

However, two equivalents of β-alanine was not enough for complete dissolution of copper hydroxocarbonate, even after prolonged heating. Between 3 or 4 equivalents required in my experiment. Two explanations are possible: either the compound has more β-alanine molecules (possibly acting as ligand), or it is not stable in water solution without excess of β-alanine.

Crystal was grown using slow evaporation method, for 2 weeks approximately.

It has very deep blue-violet color, which is not reproduced well by a monitor (can't get that violet tinge even after adjusting colors).

Unfortunately, it is very unstable on air: dehydration starts in few minutes. At the end of the photo session, it already developed small white spots on the surface. This suggests that it has many molecules of crystalline water.
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Crystals of a rare hexagonal shape.
The compound is a double salt, guanidinium aluminium sulfate hexahydrate:

C(NH2)3Al(SO4)2*6H2O

These are not final crystals, just nice samples obtained during recrystallization of the crude compound. I am going to grow larger samples later.

I learned about this compound from this page: http://www.myttex.net/forum/Thread-Solfato-di-guanidina-e-alluminio-III-esaidrato-Sintesi
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I prepared this compound for another experiment, but during recrystallization step noticed that it easily forms large crystals, so used part of the solution to grow a single crystal.

The formula is (probably) Na3[Al(C2O4)3]*5H2O

Some sources state that it has 3 molecules of H2O, but it seems to be a mistake due to potassium analog.

It is aluminium analog of sodium ferrioxalate

which has very similar though more vividly colored crystals.

Again, similarly to its ferric sibling, it has high solubility exceeding 50g per 100ml and grows easily, but is not stable on air: after few days of exposure to air, it would lose transparency and turn white. I am currently storing it under a layer of liquid paraffin.

Crystal size is about 4cm along the longest face, growing method was slow evaporation (I rarely have success with other methods), growth time is less than 2 weeks.

Preparation

To prepare this compound, I dissolved Al metal in NaOH solution, then added stoichiometric amount of oxalic acid and heated while stirring until complete dissolution of precipitate. Total equation is:

2 Al + 6 NaOH + 6 H2C2O4 = 2 Na3[Al(C2O4)3] + 6 H2O + 3 H2(g)
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Crystals of lithium ferric EDTA, a lithium analog of this compound: https://photos.app.goo.gl/iTWDMDqw531YZrFg2

I obtained these crystals experimentally and have no literature references.

The formula is Li[Fe(edta)], where edta stands for ethylenediaminetetraacetate ligand.

Compared to the sodium analog, lithium compound has the same dark brown color, but crystal shape is very different, crystals being almost cubic. Solubility is significantly higher, around 51 g/100ml at room temperature.

Crystals are stable on air.

Preparation: take 1 mol of EDTA acid suspended in water (it has low solubility), add 1 mol of LiOH, then 1 mol of Fe(OH)3 and heat with stirring until complete dissolution of solids.
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Crystals of lithium sulfate, Li2SO4*H2O.

As always, grown using slow evaporation method, rather slowly: growth took whole month.

They are stable on air.
Lithium sulfate
Lithium sulfate
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Crystalline aggregate of sodium ferric ethylenediaminetetraacetate, Na[Fe(C10H12N2O8)] or simply Na[Fe(edta)].

I prepared it by mixing hot concentrated solutions of Trilon-B (disodium edta), FeCl3 and NaOH in 1:1:2 molar ratio and crystallizing the compound (it is less soluble than the byproduct NaCl).

They have low symmetry and complex shape, with striations visible on some faces. Obtaining single crystals is somewhat complicated, because this compound nucleates really easy, but polycrystalline aggregates look great. Small crystals have brown color, bigger are almost black.

Crystals grown from aqueous solution, using slow evaporation method, growth time is around 3 weeks. Solubility of the compound is relatively low, my own measurements give 11g/100ml. Crystals are stable on air.
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Finally, a rare hexagonal crystal in my collection: lithium potassium sulfate
*LiKSO4*.

The crystal was grown from the aqueous solution. Growth time is 3 weeks, so it is growing quite slowly.

The biggest complication for growing was that this double salt does not crystallize from stoichiometric solutions: if equal molar amounts of Li2SO4 and K2SO4 are dissolved in water, then the less soluble pure K2SO4 starts crystallizing first upon evaporation. To grow crystals of double salt, mass ratio K2SO4 : Li2SO4 must be in the range from 0.05 to 0.4 (according to http://aip.scitation.org/doi/10.1063/1.4977190). Thus, the solution must have at least 2x molar excess of Li2SO4. As consequence, during evaporation concentration of K gradually drops and must be restored periodically by dissolving more potassium sulfate.

The shape is straight hexagonal "barrel": a prism with additional facets along the base edges.
Initially, it was a simple straight hexagonal prism; later, additional facets started developing. It could be caused by changes in the solution composition.
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