{"id":7184,"date":"2018-03-13T08:42:15","date_gmt":"2018-03-13T08:42:15","guid":{"rendered":"http:\/\/www.experimentoscientificos.es\/?page_id=7184"},"modified":"2022-02-22T12:42:54","modified_gmt":"2022-02-22T12:42:54","slug":"cristalizacion","status":"publish","type":"page","link":"https:\/\/www.experimentoscientificos.es\/en\/cristalizacion\/","title":{"rendered":"Crystals and Crystallisation - Characteristics and Experiments"},"content":{"rendered":"

WHAT IS CRYSTALLISATION<\/h2>\n

The\u00a0crystallisation<\/b>\u00a0is a process by which ions, atoms or molecules of a gas or liquid form a crystal lattice, the basic unit of a crystal.\u00a0<\/sup><\/p>\n

WHAT IS A CRYSTAL<\/h2>\n

A crystal is mainly characterised by the fact that it is ordered matter. The matter is externally ordered, always presenting naturally flat and shiny faces, as can be seen in the quartz in this photo:<\/p>\n\n

Moreover, the order of crystals is not only external, crystals have an internal order, which in turn is responsible for the characteristics of the crystals. There is always the unit cell. The unit cell is a set of atoms that repeats itself in space. In this picture you can see the crystal of salt, sodium chloride. It is an ordered structure of repeating NaCl molecules.<\/p>\n

Glass is often confused with crystal, it is precisely this ordered structure that differentiates them. Glass is amorphous, whereas a crystal is perfectly symmetrical. Schematically this image would differentiate between glass and crystal. The crystal would be the image on the left and the glass on the right.<\/p>\n

\"metafora<\/p>\n

CRYSTALLISATION IN THE LABORATORY<\/h2>\n

We are going to leave aside the natural crystallisation that occurs in nature, where more factors of time, pressure and temperature are involved, and we are going to see how we can forming crystals in the laboratory<\/strong>.<\/p>\n

In the laboratory, we can easily obtain crystals of different materials, where its solubility at room temperature is much lower than at higher temperatures.<\/strong>. In this way, a quantity of the material is dissolved, saturating the solution at the highest temperature, and as the temperature cools and decreases, the non-soluble part will form crystals. The slower the cooling, the larger the crystals.<\/p>\n

PRODUCTS FOR CRYSTALLISATION IN THE LABORATORY<\/h2>\n

Some products with which crystallisation can be achieved in the laboratory in a relatively simple way are the following:<\/p>\n

Copper Sulphate<\/h3>\n

Potassium Alum<\/h3>\n

See\u00a0 crystallisation with potassium alum<\/a><\/p>\n

CRYSTALLISATION EXPERIMENTS<\/h2>\n
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Calcium Chloride Silicate Crystallisation - Jard\u00edn Qu\u00edmico<\/a><\/h3><\/div>\n\n<\/strong> This experiment shows how calcium silicate crystals grow almost spontaneously and immediately in a solution of sodium silicate in water. <\/div>\n\n<\/div>\n
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Hot Ice Making Experiment (Instant Crystallisation)<\/a><\/h3><\/div>\n\n<\/strong> This spectacular experiment is not only very useful for use in instant heat packs, but also generates a rapid crystallisation reaction. <\/div>\n\n<\/div>\n
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Chemical Garden Making Experiment<\/a><\/h3><\/div>\n\n<\/strong> In the chemical garden experiment we can see how chemical crystals grow in a container. You will be able to get structures like an aquarium, with corals. <\/div>\n\n<\/div>\n
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PROPERTIES OF CRYSTALS<\/h2>\n

Because of their crystalline structure, with a repeating crystal lattice (see picture above), crystals have these common characteristics:<\/p>\n

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  1. Symmetry. Crystals have symmetry about some axis. An object has symmetry if some operation can be performed on it so that it remains identical to itself. There are 32 different types of symmetry in crystals. They are called the thirty-two kinds of crystals.<\/li>\n
  2. Homogeneity. Crystalline matter is homogeneous, the repeating motif is always the same group of atoms.<\/li>\n
  3. Anisotropy. The physical properties of crystals are not the same in all directions. It depends on the axis of symmetry and the distribution of the crystal lattice. Thus a crystal can have very strong bonds in one x-direction and weak bonds in another direction.<\/li>\n
  4. Crystals have a non-diffuse and well-defined diffraction of light. This is explained by the fact that when a ray of light enters a crystal, it is reflected very sharply and in a beam, without being diffracted.<\/li>\n<\/ol>\n

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    LEARN MORE<\/h2>\n