Chemistry Students: Remember the Water of Crystallization

Chemistry, Education
[caption id="attachment_24966" align="alignright" width="480"] Don't forget the water.[/caption] Chemicals are, for the most part, categorized into inorganic compounds and organic compounds. The expression "water of crystallization" is rarely applied to organic compounds, since most of them are not water soluble, and if they are, few even of those form crystals with water. What IS Water of Crystallization? A high percentage of water-soluble inorganic salts form crystals that include water in their crystal lattice. An example of a salt, with and without water of crystallization is cupric sulfate.1 Such salts, deprived of water content, are termed anhydrous. In our example, we might speak of copper sulfate anhydrous.2 Quantity of Water [caption id="attachment_24967" align="alignright" width="380"] Fine crystals of copper sulfate pentahydrate.[/caption] Hydrated copper sulfate includes 5 molecules of water in its crystalline…
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The Molecular Structure of Sodium Metasilicate Anhydrous

The basic formula for sodium metasilicate (water glass) includes two sodium, one silicon, and three oxygen atoms. When it includes no trace of water, the meta-silicate is anhydrous. Its formula should then be Na2SiO3, right? Well, yes. But, to leave it at that would be less than truthful. Parts, Just Parts Sodium meta-silicate can be visualized in two parts. One part is the two sodium ions Na+, each with a +1 charge. The other part is the meta-silicate (SiO3)-2 with its minus two charge. Some atoms can link to form chains. These atoms include carbon, boron, and silicon. Silicon and oxygen atoms of sodium meta-silicate molecules form a polymeric, corner bonded tetrahedra complex. This complex appears as if it has sub-units of SiO4 (silicon atoms central in tetrahedra). Note the SiO4…
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