Magnesium nitride, which possesses the

chemical formula In chemistry, a chemical formula is a way of presenting information about the chemical proportions of atoms that constitute a particular chemical compound or molecule, using chemical element symbols, numbers, and sometimes also other symbol ...

Mg₃N₂, is an inorganic compound of

magnesium Magnesium is a chemical element with the symbol Mg and atomic number 12. It is a shiny gray metal having a low density, low melting point and high chemical reactivity. Like the other alkaline earth metals (group 2 of the periodic ta ...

and

nitrogen Nitrogen is the chemical element with the symbol N and atomic number 7. Nitrogen is a nonmetal and the lightest member of group 15 of the periodic table, often called the pnictogens. It is a common element in the universe, estimated at se ...

. At room temperature and pressure it is a greenish yellow powder.

Preparation

* By passing dry nitrogen over heated magnesium: ::

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* or ammonia: ::

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History

When isolating

argon Argon is a chemical element with the symbol Ar and atomic number 18. It is in group 18 of the periodic table and is a noble gas. Argon is the third-most abundant gas in Earth's atmosphere, at 0.934% (9340 ppmv). It is more than twice as ...

William Ramsay Sir William Ramsay (; 2 October 1852 – 23 July 1916) was a Scottish chemist who discovered the noble gases and received the Nobel Prize in Chemistry in 1904 "in recognition of his services in the discovery of the inert gaseous element ...

passed dry air over

copper Copper is a chemical element with the symbol Cu (from la, cuprum) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pinkis ...

to remove

oxygen Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as ...

and over

to remove the

, forming magnesium nitride.

Chemistry

Magnesium nitride reacts with water to produce

magnesium hydroxide Magnesium hydroxide is the inorganic compound with the chemical formula Mg(OH)2. It occurs in nature as the mineral brucite. It is a white solid with low solubility in water (). Magnesium hydroxide is a common component of antacids, such as milk ...

and

ammonia Ammonia is an inorganic compound of nitrogen and hydrogen with the formula . A stable binary hydride, and the simplest pnictogen hydride, ammonia is a colourless gas with a distinct pungent smell. Biologically, it is a common nitrogenous wa ...

gas, as do many metal

nitride In chemistry, a nitride is an inorganic compound of nitrogen. The "nitride" anion, N3- ion, is very elusive but compounds of nitride are numerous, although rarely naturally occuring. Some nitrides have a find applications, such as wear-resistant ...

s. :Mg₃N_2(s) + 6 H₂O_(l) → 3 Mg(OH)_2(aq) + 2 NH_3(g) In fact, when magnesium is burned in air, some magnesium nitride is formed in addition to the principal product,

magnesium oxide Magnesium oxide ( Mg O), or magnesia, is a white hygroscopic solid mineral that occurs naturally as periclase and is a source of magnesium (see also oxide). It has an empirical formula of MgO and consists of a lattice of Mg2+ ions and O2− ions ...

. Thermal decomposition of magnesium nitride gives magnesium and nitrogen gas (at 700-1500 °C). At high pressures, the stability and formation of new nitrogen-rich nitrides (N/Mg ratio equal or greater to one) were suggested and later discovered. These include the Mg₂N₄ and MgN₄ solids which both become thermodynamically stable near 50 GPa. The Mg₂N₄ is composed of exotic ''cis''-tetranitrogen N₄⁴⁻ species with N-N bond orders close to one. This Mg₂N₄ compound was recovered to ambient conditions, along with the N₄⁴⁻ units, marking only the fourth polynitrogen entity bulk stabilized at ambient conditions.

Uses

Magnesium nitride was the

catalyst Catalysis () is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst (). Catalysts are not consumed in the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recyc ...

in the first practical synthesis of borazon (cubic

boron nitride Boron nitride is a thermally and chemically resistant refractory compound of boron and nitrogen with the chemical formula BN. It exists in various crystalline forms that are isoelectronic to a similarly structured carbon lattice. The hexagonal ...

Robert H. Wentorf, Jr. Robert H. Wentorf Jr. (May 28, 1926, in West Bend, Wis. – April 3, 1997, in Easton, N.Y.) was a staff scientist at General Electric Corporate Research and Development Laboratory in Schenectady, N.Y. and a professor of chemical engineering at ...

was trying to convert the hexagonal form of boron nitride into the cubic form by a combination of heat, pressure, and a catalyst. He had already tried all the logical catalysts (for instance, those that catalyze the synthesis of

diamond Diamond is a solid form of the element carbon with its atoms arranged in a crystal structure called diamond cubic. Another solid form of carbon known as graphite is the chemically stable form of carbon at room temperature and pressure, ...

), but with no success. Out of desperation and curiosity (he called it the "make the maximum number of mistakes" approach), he added some magnesium wire to the hexagonal boron nitride and gave it the same pressure and heat treatment. When he examined the wire under a microscope, he found tiny dark lumps clinging to it. These lumps could scratch a polished block of boron carbide, something only diamond was known to do. From the smell of ammonia, caused by the reaction of magnesium nitride with the moisture in the air, he deduced that the magnesium metal had reacted with the boron nitride to form magnesium nitride, which was the true catalyst.

Preparation

History

Chemistry

Uses

References

Further reading