Speaker 1: Welcome to brain Stuff, a production of iHeart Radio, Hey
Speaker 1: Brainstuff Lauren Bolg bomb here. Gallium is a rare, silvery
Speaker 1: white element that can pull off one of the coolest
Speaker 1: parlor tricks on the periodic table. At room temperature, gallium
Speaker 1: is a shiny metallic solid that resembles pure aluminum. But
Speaker 1: hold it in your hands for a few minutes and
Speaker 1: this solid hunk of metal starts to melt. The melting
Speaker 1: point of gallium is just eighty five point six degrees fahrenheit.
Speaker 1: That's twenty nine point eight celsius, which means that it
Speaker 1: melts into a mirror like puddle in your hot little hand.
Speaker 1: In its liquid form, gallium looks a lot like mercury,
Speaker 1: but gallium isn't toxic like mercury, so it's safer to handle,
Speaker 1: though it can stain your skin. But gallium is so
Speaker 1: much more than fodder for melt in your hand YouTube videos.
Speaker 1: It's also a key ingredient in LED lights and the
Speaker 1: go to semi condu after material for the powerful microchips
Speaker 1: in your smartphone. The only thing stopping gallium from taking
Speaker 1: over the electronics world is that it's very rare and
Speaker 1: very expensive compared to silicon. Pure gallium doesn't exist in
Speaker 1: its shiny elemental form in nature. It needs to be
Speaker 1: extracted from minerals like box site through a multi step
Speaker 1: chemical process. According to the U S Geological Survey, the
Speaker 1: abundance of gallium in Earth's crust is a measly nineteen
Speaker 1: parts per million. The silicon, by comparison, is two d
Speaker 1: and eighty two thousand parts per million. In the year
Speaker 1: eighteen fifty seven, a French chemist was the first person
Speaker 1: to isolate and recognize gallium as a new element. He
Speaker 1: named it after the Latin name for France, Gallia. But
Speaker 1: four years before that, Russian chemist Dmitri mend to Leave
Speaker 1: predictive gallium's existence. Mend to Leave, known as the father
Speaker 1: of the periodic table, saw that there was a gap
Speaker 1: in the table after aluminum, so he posited that a
Speaker 1: missing element would share many of the properties of aluminum,
Speaker 1: but with a different atomic structure. Amanda Leave was right,
Speaker 1: but he couldn't have predicted how gallium's unusual qualities somewhere
Speaker 1: between a metal and a non metal, would make it
Speaker 1: ideal for modern electronics. Here's another cool and somewhat bizarre
Speaker 1: fact about gallium. While it melts that the aforementioned hand temperature,
Speaker 1: it doesn't boil until it reaches over a scorching four
Speaker 1: thousand degrees fahrenheit or two thousand degrees celsius. It's exact
Speaker 1: boiling point is listed differently in different chemistry texts, and
Speaker 1: I'm not going to check it personally today, so that's
Speaker 1: the ballpark. At any rate. This earns gallium the award
Speaker 1: for maintaining the longest liquid phase of any element. So
Speaker 1: why is this for? The article this episode is based on.
Speaker 1: Has to Works reached out to the American Chemical Society
Speaker 1: and spoke with Daniel Mandiola, a chemistry professor at the
Speaker 1: University of Pennsylvania. He said, gallium is confused. It melts
Speaker 1: at a low temperature, which is consistent with a light element,
Speaker 1: but it boils at a very high temperature, which is
Speaker 1: consistent with a very heavy element. Gallium doesn't know if
Speaker 1: it wants to be a metal or a non metal.
Speaker 1: Gallium's dual personality stems from where it sits on the
Speaker 1: periodic table among two groups called the metalloids and the
Speaker 1: post transition metals. Gallium is next in line after aluminum,
Speaker 1: but it's atoms are far more independent than its shiny
Speaker 1: foil uh. Also, aluminum is more electro positive trait of
Speaker 1: true metals. That means it's more apt to release electrons
Speaker 1: Like silicon. Gallium is a good conductor of electricity, but
Speaker 1: not a great one. That's what makes both of these
Speaker 1: metalloids prime candidates for semiconductors where the flow of electricity
Speaker 1: needs to be control but using current manufacturing processes, A
Speaker 1: wafer of gallium arsenide, the most popular gallium based semiconductor material,
Speaker 1: is roughly a thousand times more expensive than the silicon
Speaker 1: wafer because of gallium's rarity. Even though gallium is that
Speaker 1: much more expensive than silicon, it's become a popular semiconductor
Speaker 1: material in the latest generations of smartphones. Smartphones communicate with
Speaker 1: cellular data networks using radio frequency chips or r F chips,
Speaker 1: and r F chips made with gallium arsenide give off
Speaker 1: less heat than silicon and can operate at higher frequency bands,
Speaker 1: a requirement for five G networks. A little more than
Speaker 1: of all the gallium consumed in the United States is
Speaker 1: used to make r F chips and other types of
Speaker 1: integrated circuits. However, one of the coolest applications of gallium
Speaker 1: is in light emitting diodes, or l eds, which are
Speaker 1: now used in everything from computer displays to traffic lights
Speaker 1: to car headlights. L e d s are so popular
Speaker 1: because they're super efficient they don't heat up. The first
Speaker 1: visible light l eds were invented in the early nineteen
Speaker 1: sixties when researchers at General Electric discovered the unique properties
Speaker 1: of diodes made with various gallium alloys, that is, combinations
Speaker 1: of gallium with arsenic, nitrogen, phosphorus, and other elements. In
Speaker 1: a diode, electrons move through two layers of semiconductor material,
Speaker 1: one with a positive charge and the other with a
Speaker 1: negative charge. As free electrons from the negative side fill
Speaker 1: holes in the positive side, they emit a photon of
Speaker 1: light as a byproduct. Scientists have discovered that different gallium
Speaker 1: alloys emit photons of different visible light frequencies. So gallium
Speaker 1: arsenide and gallium phosphide produced red, orange, and yellow light,
Speaker 1: while gallium nitride produces blue light. And not only do
Speaker 1: l e d s produced light when connected to electricity,
Speaker 1: but the process can be reversed. The special diodes inside
Speaker 1: of solar cells are also made of galleum based semiconductors.
Speaker 1: They take incoming light and separate it into free electrons
Speaker 1: and holes, a generating voltage that can be saved in
Speaker 1: a battery as electricity. The aerospace industry has been hot
Speaker 1: on gallium for decades. All of the high end solar
Speaker 1: panels that power satellites and long range spacecraft are made
Speaker 1: with gallium arsenide, including the critical solar panels on the
Speaker 1: Mars Exploration Rovers. At peak performance, the galleum based solar
Speaker 1: cells on the Mars Rovers could produce nine hundred watt
Speaker 1: hours of energy per martian day. But wait, there's more.
Speaker 1: A Mendiola said. Medicine is beginning to use gallium too,
Speaker 1: for detecting and treating certain types of cancers. Gallium sixty
Speaker 1: seven is attracted to cells that replicate faster than normal,
Speaker 1: which is what happens in a tumor. Gallium sixty seven
Speaker 1: as a radioactive isotope of gallium that emits non toxic
Speaker 1: gamma rays. A Radiologists can scan a patient's whole body
Speaker 1: for tumors or inflammation from an infection by injecting gallium
Speaker 1: sixty seven into their bloodstream. Because gallium sixty seven binds
Speaker 1: to clumps, of fast growing cells. Those potential trouble spots
Speaker 1: will then show up on a scan that's sensitive to
Speaker 1: gamma rays. Gallium nitrate has also shown effectiveness in shrinking
Speaker 1: and killing certain types of tumors, not just detecting them.
Speaker 1: Today's episode is based on the article gallium boiled four
Speaker 1: thousand and forty four degrees fahrenheit but will also melt
Speaker 1: in your hand on how staff works dot Com. Written
Speaker 1: by Dave Ruse. Brain Stuff is productive i Heart Radio
Speaker 1: in partnership with how stuff works dot Com and it's
Speaker 1: produced by Tyler Clang. Four more podcasts from my heart Radio.
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