Modern studies of substances allow us to discover all their new possibilities. And that means significantly expanding the main areas of application. For example, in agriculture, hundreds of different fertilizers are known that can help cultivated plants grow, grow and bear fruit. Just one of these is Chilean nitrate, which was discovered back in the XVIII century.
Name synonyms
Interestingly, for a single substance, whole series of different names are sometimes characteristic. After all, some are given by people in everyday life, others come from a deposit, others are sources from a rational chemical nomenclature of compounds.
This happened with the substance in question. Chilean saltpeter has the following synonyms for name:
- sodium nitrate;
- sodium nitrate;
- sodium nitrate;
- sodium nitrate;
- nitronatrite.
Each of them reflects some information about this substance. For example, sodium nitrate indicates the composition of the compound, and therefore, shows what the chemical formula of nitrate will be. The same information gives us some other synonyms. The word "Chilean" uniquely characterizes the main sources of deposits of this mineral.
The chemical formula of nitrate
The elemental composition of a substance is characterized by the following components: one sodium atom, one nitrogen atom and three oxygen atoms. Therefore, we can conclude how from a chemical point of view will look Chilean nitrate. The formula will be written as NaNO 3 . As a percentage, the qualitative composition will be expressed as follows: 26/16/58%, respectively.
The crystal structure of the molecular lattice of sodium nitrate is trigonal rhombohedra. In them, oxygen atoms closely group around central nitrogen, being held near it by covalent polar interactions. Thus, a single NO 3 - ion is formed , which is called the acid residue. Moreover, in the external sphere there is a positively charged sodium cation Na + . Therefore, a strong electrostatic attraction arises between oppositely charged particles. As a result, an ionic bond is formed.
The type of crystal is similar to that of feldspar (calcite). Therefore, such a structure has not only Chilean nitrate. The chemical formula immediately reflects two types of chemical bonds in the molecule:
The order of the connection of atoms in the molecule is also clearly traced; therefore, the valencies and oxidation states of both atoms and ions can be easily calculated using the formula.
Chemical class
Among inorganic compounds there is a great variety. Therefore, it is customary to divide all of them into classes according to their properties and according to the peculiarities of the composition and structure of molecules.
Chilean nitrate is no exception. The formula NaNO 3 shows that this compound is a typical salt of nitric acid. Sodium, which consists of an alkali metal cation and an acid residue of one of the most powerful oxidizing agents.
Thus, it is possible to unambiguously determine where Chilean nitrate belongs to the class of inorganic middle salts.
Physical properties
According to these parameters, the substance in question can be characterized as follows.
- A colorless crystalline substance, sometimes with a yellowish, reddish or gray tint.
- Crystals are long needle structures.
- It is odorless.
- It tastes unpleasant, very salty.
- The melting point is 308 about C.
- If heated above 380 ° C, then, like all nitrates, Chilean nitrate decomposes with the formation of metal nitrite and oxygen.
- It dissolves quite well in water (at 100 176 grams of salt, at 0 about 77 grams).
- It also dissolves quite well in ammonia and hydrazine, and in organic solvents such as ethanol, methanol or pyridine, the solubility drops sharply.
- With a certain treatment, it becomes an explosive, however, it is difficult to use nitrate as such due to too good hygroscopicity.
Considering the last parameter, sodium nitrate is stored in tightly packed plastic bags that do not allow moisture to pass through. It is also possible to find nitrate in dark glass jars with ground stoppers. The main condition is fencing from excessive lighting, temperature and humidity. If all conditions are met, the substance retains friability and dryness, the crystals will be small.
Chemical properties
As we explained earlier, Chilean nitrate is a class of inorganic compounds called salts. Chemical properties will be determined by this particular feature.
- It exhibits oxidative abilities when interacting with non-metals (sulfur, carbon). Reactions take place when the mixture is heated.
- It decomposes at temperatures above 380 o C.
- It enters into a reaction according to the type of exchange with salts of other metals, if the Bertollet rule is observed as a result of the reaction (gas is released, a precipitate forms or a poorly dissociable substance is formed).
It is the chemical properties that largely explain the features of the use of sodium nitrate.
Receiving in the industry
There are several ways in which the formation of sodium nitrate is possible.
- Direct interaction of sodium alkali metal with an oxidizing agent (nitric acid). As a result, a substitution reaction occurs, nitrate is formed, nitrogen gas, nitrogen oxides II and I, and water are released.
- The reaction between sodium oxide and nitric acid. It turns out sodium nitrate and water.
- The interaction of soda or sodium hydroxide with nitrogen oxides I and II (their mixture is called nitrous gas).
- Exchange interaction between calcium nitrate and sodium sulfate. As a result, a precipitate of poorly soluble calcium sulfate and a solution of nitrate are formed.
- Another laboratory method is the reaction between ammonium nitrate and baking soda or alkali.
- The method also used in the laboratory is the interaction by the exchange mechanism between silver nitrate (colloquially lapis) and ordinary rock salt, that is, sodium chloride.
- An industrial method, or a method used in production, is leaching and subsequent crystallization from deposits, which is carried out by the countercurrent method.
Today, these are all methods by which it is possible to obtain a sufficient amount of sodium nitrate.
Mining and deposits
The main deposits of the substance in question:
- Chile;
- southwest Africa;
- California.
The remaining places are not so rich in terms of the content of the compound. Chileans have always been involved in the largest export deliveries of raw materials. This is due to one of the names of sodium nitrate.
Chilean nitrate is a source of nitrogen for plants, as its main historically established area of application is agriculture, where it acts as a fertilizer.
Areas of use
For the first time this miraculous means of fertilizing the soil became known in 1825. However, then saltpeter did not find its buyer and remained forgotten. Five years later, it was used to aid in plant nutrition for the first time and was amazed at the results. Since then, the consumption of this fertilizer has become widespread. By 1870, it reached 150 thousand tons per year!
Today, agriculture is far from the only area in which Chilean nitrate is needed. Application has significantly expanded its boundaries.
- As a preservative for meat and sausage products in the food industry.
- Raw materials for the production of smoke powder and other explosives.
- Metal industry.
- The manufacture of heat storage compounds.
- In the production of glass.
- For the manufacture of saltpeter mixture - salt refrigerant nature.
- In rocket fuel.
- In pyrotechnic products.
Obviously, the areas of application of sodium nitrate are quite extensive. In addition, for a long time it remained practically the only source for the synthesis of nitric acid. Today, it is no longer used for these purposes, since acid is produced by alternative synthetic methods.