YTTRIUM

Name: Yttrium

Symbol: Y

Group: 3

Period: 5

Block: d

Category: Transition metals

Atomic number: 39

Atomic mass: 88.905 u

Electrons per shell: 2, 8, 18, 9, 2

Electronegativity: 1.22

Density: 4.472 g/cc

Melting point: 1526°C

Boiling point: 3345°C

Thermal conductivity: 17 W (m K)

Electrical conductivity: 1.8 × 10^6 S/m

Magnetic order: Paramagnetic

Ordinary state: Solid

Oxidation states: 0, 1, 2, 3

Mohs hardness: 8.5* (unconfirmed)

Vickers Hardness: No data

Brinell Hardness: 588 MPa

Most stable isotopes: Y-89 (100%, monoisotopic element)

Discoverer: Heinrich Rose, German (1843)

Yttrium, a metal not to be confused with ytterbium despite their similar names, takes its designation in honor of Ytterby, a region near Stockholm, Sweden, a historical birthplace of numerous rare earth discoveries. This connection is not accidental, as both yttrium and ytterbium, along with other elements, were identified in minerals extracted from this area, known for its richness in lanthanides. Yttrium, classified as a pseudo-lanthanide, resembles elements of this family more than typical transition metals due to its chemical and physical properties. Minerals containing yttrium are often naturally associated with lanthanides, a reflection of their geological formation in Ytterby, a locality that has marked the history of rare earths—a term referring to the oxides of these elements, including the lanthanides.

Yttrium shares Group 3 of the periodic table with scandium, with which it has significant similarities, an expected trend given its chemical positioning. This relationship with the lanthanides and its origin in Ytterby underscore yttrium's importance in the study of rare earths, consolidating its relevance in modern chemistry and its connection to a place that has been key to scientific advancements in this field.

Yttrium, like scandium, stands out for its resemblance to the lanthanides more than to typical transition metals, although both are classified within this category. Its crystalline structure makes it mechanically challenging: it is hard, brittle, and easily pulverizable, limiting its applications in its pure state. With a silver-gray color that it retains in air when in massive form, yttrium is notably reactive, surpassing even scandium in this aspect, making it unsuitable for direct uses without alloys or specific treatments.

Frequently found in association with lanthanides in mineral deposits, yttrium is considered an unofficial member of this group due to its shared chemical properties. However, its industrial importance lies not so much in the elemental metal as in its oxide, yttria (Y₂O₃). This compound plays a crucial role in sectors such as metallurgy and electronics, where it is valued for its stability and versatility in high-tech applications, from ceramic coatings to advanced electronic components.

Yttrium exhibits limited corrosion resistance, sufficient only for storage in dry air. Its high reactivity makes it vulnerable even in fresh water at room temperature, a behavior that intensifies when the metal is finely divided or in powder form, where it can spontaneously ignite in the presence of oxygen. This characteristic distinguishes it from less reactive metals, and its susceptibility increases as its volume decreases. In moderately corrosive environments, such as acids or alkalis, yttrium offers no significant resistance, restricting its use in its pure state and orienting it towards applications where its oxide or alloys compensate for this limitation. 

Yttrium (Y), unlike other elements, has no significant use in its pure state or as an alloying element in metallic solutions. Its true importance in metallurgy lies in its oxide, yttria (Y₂O₃), a white powder remarkably stable against corrosion and high temperatures.

Yttria is primarily used as a stabilizer and dopant in other materials. For example, it is fundamental for stabilizing the crystalline (cubic) structure of zirconia (ZrO₂) , a high-strength ceramic material. In tungsten (W) alloys, such as those used in TIG welding, yttria is added to improve high-temperature stability, acting as a safer alternative to thoria (ThO₂) , which is radioactive. Additionally, yttria is employed in nickel (Ni) and cobalt (Co)-based superalloys and in some aluminum (Al) alloys to improve toughness and mechanical properties at high temperatures, preventing thermal expansion. However, its use in metallurgy (carbon steels and stainless steels) is insignificant.

Beyond metallurgy, yttria is used to manufacture artificial garnets, such as the famous YAG (Yttrium Aluminum Garnet). These materials have applications in electronics, including cathode ray tubes, lasers, and "cold light" lamps.

Friedrich Wöhler is often erroneously credited with the discovery of yttrium, but in 1842, what he obtained was yttrium chloride, not the element in its pure form. The credit for the definitive isolation falls to Heinrich Rose, who in 1843 succeeded in extracting elemental yttrium. Although both scientists were German, yttrium is deeply linked to Sweden, particularly the region of Ytterby, from which its name derives. This metal is considered one of Sweden's "flagship elements" and, by extension, of Scandinavia, due to its association with the rich rare earth deposits in the area, which have marked a milestone in the history of chemistry.