Elizabeth Henderson
Product Development Manager ITAC Ltd |
Magnesium’s most important job on earth is to work in the
chlorophyll molecule, capturing energy from the sun. Chlorophyll molecules are
porphyrins, all of which have four nitrogen atoms providing a site for a metal
ion in the centre. In particular, chorophyll has magnesium in this site, and
the molecule absorbs red and blue light for synthesis of sugars from water and
carbon dioxide. Without this chemistry, there would be no mechanism for plants to
convert energy from the sun into food and chemical fuels.
Most applications of magnesium focus on its physical
properties – because it has a low density it is incorporated in casting alloys
for racing engines and other applications where weight reduction is crucial,
but this can be a source of problems as magnesium metal is highly flammable.
Although pieces of the metal are normally covered by a thin layer of inert
oxide, if a flame is held to them they burn with a bright white flame. This
property means magnesium is a regular constituent of fireworks and safety
flares, and was a component of early flash powders for studio photography. It
was also built into early flash bulbs, where the foil was ignited
electronically to give a bright white flash without releasing any smoke.
Magnesium plays a
major role in synthesis of organic compounds, as a component of Grignard
reagents. These highly reactive species react with carbonyl groups in molecules
such as aldehydes and ketones to form of new carbon-carbon bonds. Grignard reagents
can also be used in reactions with groups as diverse as epoxies and nitriles to
alkylate a target carbon atom. They have wide applications in the synthesis of
molecules for drug intermediates.
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