Yttrium: the story on HearLore

Yttrium

In 1787, a part-time chemist named Carl Axel Arrhenius stumbled upon a heavy black rock in an old quarry near the Swedish village of Ytterby, now part of the Stockholm Archipelago. He mistook the mineral for an unknown substance containing tungsten and named it ytterbite, sending samples to colleagues across Europe for analysis. This single discovery would eventually spawn the naming of four other elements and redefine the understanding of rare-earth chemistry. The rock itself was not a new element but a complex mineral that would later be renamed gadolinite in honor of Johan Gadolin, the chemist who identified the new oxide within it in 1789. Gadolin published his complete analysis in 1794, and Anders Gustaf Ekeberg confirmed the identification in 1797, naming the new oxide yttria. At the time, the scientific community believed that discovering a new earth was equivalent to discovering the element within it, a belief that would drive decades of chemical investigation. Friedrich Wöhler is credited with first isolating the metal in 1828 by reacting a volatile chloride with potassium, though the process was difficult and the resulting metal was impure. For decades, the element remained a laboratory curiosity, its true nature obscured by the complexity of separating it from its chemical cousins. The symbol for the element was originally Yt, a convention that persisted until the early 1920s when it was simplified to Y, the symbol it bears today. The village of Ytterby, a small fishing community, became the namesake for an entire family of elements, including ytterbium, terbium, and erbium, all isolated from the original gadolinite ore. This geological accident in Sweden set the stage for the element's eventual rise from a chemical footnote to a cornerstone of modern technology.

The Silent Partner Of The Lanthanides

Yttrium exists in nature never as a free element but always locked in combination with lanthanide elements within rare-earth minerals. It is chemically so similar to the lanthanides that it is often grouped with them as a rare-earth element, despite being a transition metal in group 3 of the periodic table. The similarity is so profound that if physical properties were plotted against atomic number, yttrium would appear to have an apparent number between 64.5 and 67.5, placing it squarely between the lanthanides gadolinium and erbium. This phenomenon is attributed to the lanthanide contraction, a periodic trend that causes the atomic radius of yttrium to be nearly identical to that of heavy lanthanide ions. In solution, yttrium behaves as if it were one of these heavy lanthanides, often falling in the same range for reaction order and resembling terbium and dysprosium in its chemical reactivity. Unlike scandium, its neighbor in the periodic table, yttrium resembles the lanthanides more closely than it resembles its own group members. The element is almost exclusively trivalent, meaning it gives up all three of its valence electrons to form compounds, whereas about half the lanthanides can exhibit valences other than three. This unique chemical behavior allows yttrium to be concentrated in heavy rare-earth minerals like xenotime, which can contain as much as 60% yttrium as yttrium phosphate. The element is found in soil in concentrations between 10 and 150 parts per million, and in sea water at 9 parts per trillion. Despite its abundance in the Earth's crust at about 31 parts per million, making it the 43rd most abundant element, it is never found in nature as a free metal. The element's atomic structure, with 50 neutrons in its nucleus and a mass number of 89, makes it the only stable isotope found in the Earth's crust. This stability is thought to result from its low neutron-capture cross-section, a property that allows it to persist in the universe while other isotopes decay. The element's position in the periodic table is a testament to the complex interplay of atomic forces, where the lanthanide contraction creates a chemical mimicry that has puzzled chemists for centuries.

Common questions

When was yttrium first discovered and by whom?

Carl Axel Arrhenius discovered yttrium in 1787 when he found a heavy black rock in an old quarry near the Swedish village of Ytterby. Johan Gadolin identified the new oxide within the mineral in 1789, and Anders Gustaf Ekeberg confirmed the identification in 1797. Friedrich Wöhler first isolated the metal in 1828 by reacting a volatile chloride with potassium.

Where is yttrium found in nature and what is its abundance?

Yttrium exists in nature never as a free element but always locked in combination with lanthanide elements within rare-earth minerals. The element is found in soil in concentrations between 10 and 150 parts per million and in sea water at 9 parts per trillion. It is the 43rd most abundant element in the Earth's crust at about 31 parts per million.

How was yttrium created in the solar system?

Yttrium in the Solar System was created by stellar nucleosynthesis mostly by the s-process which accounts for approximately 72% of its existence. The s-process is a slow neutron capture of lighter elements inside pulsating red giant stars such as Mira. The r-process accounts for the remaining 28% and consists of rapid neutron capture by lighter elements during supernova explosions.

What are the primary modern uses of yttrium in technology and medicine?

The most important present-day use of yttrium is as a component of phosphors especially those used in LEDs and television set cathode ray tube displays. Yttrium is a key ingredient in the yttrium barium copper oxide superconductor developed at the University of Alabama in Huntsville and the University of Houston in 1987. The radioisotope yttrium-90 is used to label drugs for the treatment of various cancers including lymphoma and leukemia.

What is YInMn blue and when was it discovered?

In 2009 Professor Mas Subramanian and associates at Oregon State University discovered that yttrium can be combined with indium and manganese to form an intensely blue pigment known as YInMn blue. This was the first new blue pigment discovered in 200 years and is intensely blue non-toxic inert and fade-resistant. The pigment is formed by heating yttrium indium and manganese oxides together resulting in a crystalline structure that absorbs light to produce a vivid blue color.

Is yttrium toxic to humans and what are the safety limits?

Yttrium can be highly toxic to humans animals and plants with water-soluble compounds considered mildly toxic while insoluble compounds are non-toxic. The Occupational Safety and Health Administration limits exposure to yttrium in the workplace to 5 milligrams per cubic meter over an 8-hour workday. At levels of 50 milligrams per cubic meter yttrium is immediately dangerous to life and health.

The Star Born In Red Giants

Yttrium in the Solar System was created by stellar nucleosynthesis, mostly by the s-process, which accounts for approximately 72% of its existence, and the r-process, which accounts for the remaining 28%. The s-process is a slow neutron capture of lighter elements inside pulsating red giant stars, such as Mira, an example of the type of red giant star in which most of the yttrium in the solar system was created. The r-process consists of rapid neutron capture by lighter elements during supernova explosions. Yttrium isotopes are among the most common products of the nuclear fission of uranium in nuclear explosions and nuclear reactors. In the context of nuclear waste management, the most important isotopes of yttrium are Yttrium-90 and Yttrium-91, with half-lives of 58.51 days and 64 hours, respectively. Yttrium-90 exists in secular equilibrium with its long-lived parent isotope, strontium-90, which has a half-life of 29 years. At least 32 synthetic isotopes of yttrium have been observed, ranging in atomic mass number from 76 to 108. The least stable of these is Yttrium-76 with a half-life of 25 milliseconds, while the most stable is Yttrium-91 with a half-life of 106.629 days. Yttrium isotopes with mass numbers at or below 88 decay mainly by positron emission to form strontium isotopes, while those with mass numbers at or above 90 decay mainly by electron emission to form zirconium isotopes. The element has at least 20 metastable or excited isomers ranging in mass number from 78 to 102. Multiple excitation states have been observed for Yttrium-89 and Yttrium-91. While most yttrium isomers are expected to be less stable than their ground states, Yttrium-91 has a longer half-life than its ground state because it decays by beta decay rather than isomeric transition. The stability of Yttrium-89, with its 50 neutrons, is thought to result from its very low neutron-capture cross-section, a property that allows it to persist in the universe while other isotopes decay. This stability is thought to result from their very low neutron-capture cross-section, a property that allows it to persist in the universe while other isotopes decay. The element's abundance in the solar system is a testament to the slow, steady processes of stellar evolution, where red giants and supernovae forge the building blocks of matter.

The Metal That Defies Gravity

Yttrium is a key ingredient in the yttrium barium copper oxide superconductor developed at the University of Alabama in Huntsville and the University of Houston in 1987. This superconductor is notable because the operating superconductivity temperature is above liquid nitrogen's boiling point of 77.1 Kelvin. Since liquid nitrogen is less expensive than the liquid helium required for metallic superconductors, the operating costs for applications would be less. The actual superconducting material is often written as YBa2Cu3O7-d, where d must be less than 0.7 for superconductivity. The reason for this is still not clear, but it is known that the vacancies occur only in certain places in the crystal, the copper oxide planes, and chains, giving rise to a peculiar oxidation state of the copper atoms, which somehow leads to the superconducting behavior. The theory of low temperature superconductivity has been well understood since the BCS theory of 1957. It is based on a peculiarity of the interaction between two electrons in a crystal lattice. However, the BCS theory does not explain high temperature superconductivity, and its precise mechanism is still a mystery. What is known is that the composition of the copper-oxide materials must be precisely controlled for superconductivity to occur. This superconductor is a black and green, multi-crystal, multi-phase mineral. Researchers are studying a class of materials known as perovskites that are alternative combinations of these elements, hoping to develop a practical high-temperature superconductor. The discovery of YBCO in 1987 was a watershed moment in materials science, proving that superconductivity could be achieved at temperatures accessible with liquid nitrogen, a breakthrough that opened the door to practical applications in power transmission, magnetic levitation, and medical imaging. The element's role in this discovery was pivotal, as it provided the structural framework necessary for the superconducting properties to emerge.

The Hidden Danger In The Dust

Yttrium can be highly toxic to humans, animals, and plants. Water-soluble compounds of yttrium are considered mildly toxic, while its insoluble compounds are non-toxic. In experiments on animals, yttrium and its compounds caused lung and liver damage, though toxicity varies with different yttrium compounds. In rats, inhalation of yttrium citrate caused pulmonary edema and dyspnea, while inhalation of yttrium chloride caused liver edema, pleural effusions, and pulmonary hyperemia. Exposure to yttrium compounds in humans may cause lung disease. Workers exposed to airborne yttrium europium vanadate dust experienced mild eye, skin, and upper respiratory tract irritation, though this may be caused by the vanadium content rather than the yttrium. Acute exposure to yttrium compounds can cause shortness of breath, coughing, chest pain, and cyanosis. The Occupational Safety and Health Administration limits exposure to yttrium in the workplace to 5 milligrams per cubic meter over an 8-hour workday. The National Institute for Occupational Safety and Health recommended exposure limit is 5 milligrams per cubic meter over an 8-hour workday. At levels of 50 milligrams per cubic meter, yttrium is immediately dangerous to life and health. Yttrium dust is highly flammable. The element has no known biological role, and exposure to yttrium compounds can cause lung disease in humans. The toxicity of yttrium compounds is a concern for workers in the rare-earth industry, who must take precautions to avoid inhaling dust or exposure to soluble compounds. The element's chemical properties, which make it useful in many applications, also make it potentially hazardous to human health. The study of yttrium's toxicity has led to the development of safety protocols and regulations to protect workers and the public from the dangers of exposure. The element's dual nature as both a life-saving medical tool and a potential health hazard underscores the importance of responsible use and handling.