The magnesium nitrate is an inorganic solid whose chemical formula is Mg (NO3)two. It is an ionic compound formed by the union of a magnesium cation Mgtwo+ and two nitrate anions NO3-.
Mg (NO3)two it is a white crystalline solid. It is very hygroscopic, that is, it absorbs water from the environment easily. When remaining in contact with the surrounding air, it tends to form its Mg hexahydrate (NO3)two•6HtwoOR.
Magnesium Nitrate Hexahydrate Mg (NO3)two•6HtwoO has in its crystalline structure 6 molecules of water HtwoOr for each molecule of Mg (NO3)two. Magnesium nitrate is found in caverns and mines in the form of the mineral nitromagnesite.
Mg (NO3)two obtained commercially by reacting magnesium metal Mg with nitric acid HNO3.
It has a wide variety of uses, such as in agriculture as a fertilizer because it provides nutrients for plants such as nitrogen (N) and magnesium (Mg)..
It is used in the fireworks or pyrotechnic industry and also in obtaining concentrated nitric acid. Used in chemical analysis, physics experiments, and medical and scientific studies.
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Anhydrous magnesium nitrate is made up of a magnesium cation Mgtwo+ and two nitrate anions NO3-.
Magnesium ion Mgtwo+ possesses electron configuration: 1stwo, 2stwo 2 P6, 3s0, since it has given up the two electrons of the outermost shell (3s). This conformation is very stable.
The NO ion3- has a flat and symmetrical structure.
In the structure of NO3- the negative charge is continuously distributed among the three oxygen atoms.
-Anhydrous magnesium nitrate: Mg (NO3)two
-Magnesium nitrate dihydrate: Mg (NO3)two•2HtwoOR
-Magnesium nitrate hexahydrate: Mg (NO3)two•6HtwoOR
-Magnesium dinitrate
-Mg (NO3)two anhydrous: white solid, cubic crystals.
-Mg (NO3)two dihydrate: white crystalline solid.
-Mg (NO3)two hexahydrate: colorless solid, monoclinic crystals
-Mg (NO3)two anhydrous: 148.31 g / mol
-Mg (NO3)two hexahydrate: 256.41 g / mol
-Mg (NO3)two hexahydrate: 88.9 ºC
-Mg (NO3)two hexahydrate: does not boil, decomposes at 330 ºC
-Mg (NO3)two anhydrous: 2.32 g / cm3
-Mg (NO3)two dihydrate: 1.456 g / cm3
-Mg (NO3)two hexahydrate: 1,464 g / cm3
Anhydrous magnesium nitrate is very soluble in water: 62.1 g / 100 mL at 0 ºC; 69.5 g / 100 mL at 20 ° C. It is also very hygroscopic, being in contact with air quickly forms the hexahydrate.
Mg (NO3)two dihydrate is also very soluble in water and ethanol. It is hygroscopic.
Mg (NO3)two hexahydrate is also very soluble in water. It is moderately soluble in ethanol. It is the most stable of the three in contact with air, that is, of the three it is the one that absorbs the least water from the environment.
By subjecting an aqueous solution of Mg (NO3)two Upon evaporation of water, the salt that crystallizes is the hexahydrate: Mg (NO3)two•6HtwoO. Hexahydrate means that in the solid each molecule of Mg (NO3)two is bound to 6 water molecules.
There is also the dihydrate Mg (NO3)two•2HtwoOr, in which Mg (NO3)two solid is bound to 2 water molecules.
Heating Mg hexahydrate (NO3)two•6HtwoOr the anhydrous salt is not obtained, since magnesium nitrate has a high affinity for water.
For this reason, when heated above its melting point, it initially forms a mixed salt of magnesium nitrate and hydroxide Mg (NO3)two•4Mg (OH)two.
This mixed salt, upon reaching 400 ºC, decomposes to magnesium oxide MgO and nitrogen oxide gases are released..
It can be prepared by reacting magnesium carbonate MgCO3 with nitric acid HNO3, giving off carbon dioxide COtwo:
MgCO3 + 2 HNO3 → Mg (NO3)two + COtwo↑ + HtwoOR
It can also be obtained with magnesium hydroxide Mg (OH)two and nitric acid:
Mg (OH)two + 2 HNO3 → Mg (NO3)two + 2 htwoOR
Commercially it is obtained in several ways:
1- Reacting the magnesium metal Mg with nitric acid HNO3.
2- By reacting magnesium oxide MgO with nitric acid HNO3.
3- Binding magnesium hydroxide Mg (OH)two and ammonium nitrate NH4NOT3, forming the magnesium nitrate with the evolution of ammonia NH3.
Mg (NO3)two hexahydrate occurs naturally in mines and caves or caverns in the form of the mineral nitromagnesite.
This mineral is present when guano comes into contact with magnesium-rich rocks. Guano is the material resulting from the excrement of seabirds and seals in very dry environments.
Mg (NO3)two hexahydrate is used in the ceramic, chemical and agricultural industries.
This compound is a fertilizer because it provides nitrogen (N), which is one of the three basic elements required by plants, and magnesium (Mg), which is a secondary component that is also important for plants..
In this way it is used with other ingredients in greenhouses and in hydroponic cultivation. The latter consists of growing the plants in an aqueous solution with fertilizer salts instead of soil.
It is also used as a catalyst in obtaining petrochemical compounds. It allows adjusting the viscosity in certain processes. Anhydrous magnesium nitrate is used in pyrotechnics, that is, for the manufacture of fireworks.
Anhydrous magnesium nitrate is a dehydrating agent. It is used, for example, to obtain concentrated nitric acid, as it eliminates water and concentrates acid vapors up to 90-95% HNO3.
It is also used to coat ammonium nitrate and allow the formation of beads of this compressed material..
It is useful in the formulation of inks, toner (black powder used in photocopying systems) and coloring products. Serves as a magnesium standard in analytical chemistry.
The salt of magnesium nitrate and cerium Mg (NO3)two•Frown3)3 It is of interest in physics experiments at low temperatures, as it is used as a coolant in adiabatic demagnetization experiments (without heat transfer).
This magnesium and cerium salt has been used to establish extremely low temperature levels on the Kelvin scale (close to absolute zero)..
Several researchers have used Mg (NO3)two in compositions with synthetic and natural polymers to increase conductivity in magnesium ion batteries.
It has also been investigated in the construction of supercapacitors for the storage of high power energy.
Magnesium nitrate has been administered to laboratory rats with arterial hypertension (high pressure) and was found to effectively lower blood pressure and attenuate or soften the effects of complications of this disease.
It has also shown protective effects against neurological disorders (derangement in neurons) and against death in rats during carotid artery plugging processes..
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