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Crystallization in gels

2023-02-15T12:38:45+00:00

It is often the chemist's task to optimize the conditions in which he performs the reaction so that it proceeds as quickly as possible, because a faster reaction means less resources used to obtain the product, which affects the profitability of production itself. However, there are situations in which we try to slow down the reactions. For example, if we mix a solution of copper(II) sulfate (bluestone) with a solution of sodium potassium tartrate (Rochelle salt), an insoluble blue-green precipitate will immediately form. The resulting product is a very fine crystalline powder. If we wanted to make crystals from that [...]

Crystallization in gels2023-02-15T12:38:45+00:00

Prince Rupert’s Drop

2023-02-15T12:37:17+00:00

It's fascinating how much history, science and the unknown is hidden under the cover of one (ordinary) drop. In truth, it is not a drop of water, but a drop of molten and then suddenly cooled glass. Well, let's start with the story... Some call it the Prussian tear, others the Dutch tear, however the most common name for this unusual creation is Prince Rupert's tear, referring to Prince Rupert of the Rhine, Duke of Cumberland (17 December 1619 - 29 November 1682), a German-English military officer, admiral, scientist and colonial governor. It was he who brought the glass drop [...]

Prince Rupert’s Drop2023-02-15T12:37:17+00:00

Column chromatography

2023-02-15T12:36:15+00:00

One of the most frequent pains of almost every chemist dealing with the synthesis of new organic compounds is precisely the fact that almost no known reaction gives pure products that we can just take from the reaction mixture and proceed to do with them whatever we had in mind. On the contrary, at the end of the reaction, the reaction mixture almost always contains, along with the desired product, some compounds that we didn't want to get or that we don't need. These can be some additional substances that are created in the reaction, sometimes it is even the [...]

Column chromatography2023-02-15T12:36:15+00:00

Twinned crystals

2023-02-15T12:35:19+00:00

Undoubtedly, at some point in your life (perhaps as part of chemistry classes in elementary or high school) some of you tried to make a nice single crystal using the method of crystallization from a saturated solution. You probably tried to grow a nice, big crystal of bluestone (copper sulfate pentahydrate), table salt (sodium chloride) or maybe even citric acid, and some probably tried their hand at crystallizing ordinary table sugar (sucrose). Those who used blue stone and citric acid for the experiment certainly succeeded in growing beautiful, regular and relatively large crystals, with clearly defined edges and planes, while [...]

Twinned crystals2023-02-15T12:35:19+00:00

Epitaxial crystals

2023-02-15T12:34:19+00:00

You got familiar with chromium alum and aluminium alum in the previous article, where we explained how, due to the property of isomorphism of these two substances, we can prepare crystals of different intensity of purple colour, which comes from chromium (III) ions, by mixing their saturated solutions. Today we are continuing to talk about these two chemical compounds. We will make crystals from them again, but these will be a bit more special and, certainly, more beautiful. The focus is on the so-called epitaxial crystals, i.e. crystals in which one substance crystallizes on a crystal surface of the other [...]

Epitaxial crystals2023-02-15T12:34:19+00:00

Alums

2023-02-15T12:33:29+00:00

Alums are a distinct class of double salts described by a general formula M(I)M(III)(SO4)2x12H2O, where M(I) is a monovalent and M(III) is a trivalent metal. In addition to the formula, what all types of alum also have in common is the crystal structure - all alum types have cations, anions and water molecules distributed in space in the same way. That is why the shape of the crystals they build is identical, so all alums from aqueous solutions crystallize in the shape of a regular octahedron. Two alums that can be mixed to produce interesting crystals are chromium alum, KCr(SO4)2x12H2O [...]

Alums2023-02-15T12:33:29+00:00

Menthol

2023-02-15T12:31:56+00:00

In this cold winter weather, there is rarely anything as pleasant as a cup of hot tea, the steam of which fills the room with various aromas. While drinking my favourite drink - the simple and old one, mint tea, an interesting story came to my mind... Mint is a well-known plant with recognizable aroma that we find in teas, toothpastes, chewing gums and many other products, and we often use it in the summer months because of its refreshing taste. That taste, or aroma, comes from the chemical compound menthol. It is a natural organic compound that belongs to [...]

Menthol2023-02-15T12:31:56+00:00

Iodine

2023-02-15T12:30:55+00:00

In the lower right corner of the periodic table of elements, at the very bottom of group 17, a well-known element is hiding. Its name is iodine, and some will immediately remember the characteristic purple colour of its crystals. This element, along with fluorine, chlorine and bromine, belongs to the group of halogen elements that were named after their ability to form salts in which they are included as anions (e.g. sodium chloride, potassium bromide or cesium iodide). It is one of the elements necessary for living, given that it makes a part of the thyroid hormone. In nature, it [...]

Iodine2023-02-15T12:30:55+00:00