A shortage of helium would affect numerous areas, including medicine and other scientific fields. The uncertain future availability of helium gas is leading to an exploration of the alternatives, but why are we running so low on what seems to most of us to be a very common resource?
What is Helium?
Helium (He) is an element with atomic number 2 and atomic weight 4. Under standard conditions, He is stable as a single atom and does not tend to bond to other elements.
Two of the main characteristics of helium are:
- It is stable in the gaseous state, even at very low temperatures; its melting and boiling temperatures (- 272 and -269 oC, respectively) are the lowest for a single element.
- It is a very light gas; at 15 oC and atmospheric pressure, its density is 0.169 kg/m3, much lower than air density under the same conditions (1.225 kg/m3).
How Do We Use Helium?
Many people associate helium with the light floating balloons used at parties, but the gas is essential for several technological applications, from medicine to electronics.
Helium’s main use is as a coolant for instruments that need to operate at very low temperatures; an example is the superconducting magnet used in magnetic resonance imaging (MRI) diagnostic equipment, which works at a temperature of about -269 oC. Helium can be used to maintain instruments at such low temperatures because of its low boiling point.
Other applications include nuclear magnetic resonance (NMR) instruments used to determine the structure of some molecules. Helium is also used for some processes that require a controlled and inert atmosphere, such as the production of semiconductors and optic fibers. Gas chromatography-mass spectrometry (GC-MS), a technique used to identify gaseous compounds, can also be performed using helium as a carrier gas.
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