Scandium research paper:
The transition metals have played an important role in human history. It was these elements that were responsible for the Bronze and Iron Ages, during which advances in tools and weapons were made. Today humans are beginning to take advantage of the properties of transition metals located at the left most positions of the d-block on the periodic table.
One d-block metal that presents new technological avenues in the development of human tools is scandium. Although universally present in the earths crust, scandium is found only in trace amounts in minerals. (Scandium Information Center, 2003). Despite its scarcity, scandium has become an important human resource and has many uses.
Scandium was discovered by Lars Fredrick Nilson, a Swedish chemist, in 1878. Nilson discovered scandium, while attempting to produce a sample of pure ytterbia, another transition metal, from 10 kilograms of the mineral euxenite. (ItвЂ™s elemental, 2003) Through a series of decompositions, Nilson observed that the molecular weight of the compounds he was working with was slightly less than he would have expected. This suggested the presence of an unknown element. He gave the element its name on the basis that it had, at that time, only been found in minerals present on the Scandinavian Peninsula. (Nilson, 1880) Although Nilson is credited with the discovery of scandium, it was not until 1937 that the first metallic scandium was produced. Furthermore, it was not until 1960 that the first pure scandium was produced using more refined processing techniques. (ItвЂ™s elemental, 2003)
The name scandium is misleading because scandium is widely distributed in the earthвЂ™s crust, and is the 50th most abundant element on the planet. However, it is only found in minute quantities in over 800 types of minerals. Its discovery in Scandinavia is perhaps due to the fact that scandium is a main component in the rare mineral thortveitite, Sc2Si2O7, which is only found in this region of the world. This case is an anomaly since scandium is rarely found in high concentrations in minerals on earth. (Scandium Information Center, 2003) Scandium is mainly present in small amounts in ferromagnesian minerals such as pyroxenes, amphiboles, micas, garnets, and epidote-group minerals. (Raade, 2003)
Scandium has an atomic number of 21, and an atomic mass of 44.96 grams per mole. Therefore a scandium atom is composed of 21 protons, 21 electrons, and 24 neutrons. Its electrons occupy S, P, and D orbitals. The groundstate electron configuration of scandium is: 1s22s22p63s23p64s23d1, or [Ar]4s23d1. Since there is one unpaired electron in the d-orbital scandium is paramagnetic and will be pulled into a magnetic field. (Jones, L., 2000)
The only oxidation state of scandium is +3 since the loss of three electrons makes it isoelectronic, a noble gas. However, the first ionization energy of scandium is 631 KJ/mol, while the second is 1235 KJ/mol. This difference can be explained by the fact that removing one electron leaves scandium with a full 4s energy level. This state is slightly more stable. Therefore, removing a second electron will require more energy. (Jones, L., 2000)
Scandium is a highly reactive metal. It reacts with water as vigorously as calcium. In this reaction, the scandium ion is strongly hydrogenated, and becomes a strong Bronsted acid. A Bronsted acid is defined as a proton donor, or a source of hydrogen ions. In water, hydrogenated scandium ions will donate hydrogen ions in the creation of hydronium ions. (Jones, L., 2000)
Located in the fourth period and the third group, Scandium is a member of the D-block transition metals. All of the elements in this group are metals and have many common properties. D-block transition metals tend to be silver white in color, ductile malleable, lustrous. In most cases, these elements have high melting and boiling points. Scandium has a melting point of 1540 degrees Celsius and a boiling point 2800 degrees Celsius. Furthermore, the atomic sizes of the transition metals, especially in position four, are relatively similar, which allows them to form substitution alloys. (Jones, L., 2000) Scandium forms many aluminum alloys, which have been important for human uses. (Al-Mg Alloy Doped with Sc, 2003)
Scandium research and development is essential in producing and furthering modern technological advances, as well as common everyday items. The use most associated with scandium revolves around its formation of an alloy with aluminum. The Al3Sc compound creates a stronger internal lattice than other common alloys such as Zr, Ti, Mn, or Cr. Highly refined Al-Sc improves the weldability of the complete alloy as well as the overall strength of items prone to recrystalization. (Scandium Information Center, 2003). Thus scandium is found in high-end bicycle frame tubing, golf clubs, tennis rackets, welding wire, automobiles, baseball bats. (Al-Mg Alloy Doped with Sc, 2003)
The Al-Sc alloys are found where lightweight and strong solutions are needed. Currently, many military applications have been found for the compound alloy in aircraft. When added to aluminum compounds, scandium produces the highest increase in strength per atomic percentage point than any other element used as an alloy. Though expensive to produce, European commercial jet manufacturer, AirBus, is considering implementing the alloy into their aircraft, while boat manufacturers are exploring the benefits in hull design. The USSR was the first nation to extensively use scandium as an alternative to other compounds such as AlMg6 in their military aviation program. In the past Cold War era, Soviet scientists were highly successful with their production line of Mig-29 interceptor jets, which used Al-Sc alloys. (Scandium Information Center, 2003) NASA is using a logical extension of the technology as an ultralight substance in spacecraft and station modules. Here the alloy is praised for its resistance to corrosion when exposed to propellant, oxidation, and humidity. (Al-Mg Alloy Doped with Sc, 2003)
Al-Sc alloys are currently being expanded with new molding and shaping techniques. Bringing about change due to higher specific strength and weld capabilities, Al-Sc can now be subjected to a super plastic deformation process creating complex molds and shapes. The resulting alloy is almost impermeable due to the high level of processing and precision machining. (Al-Mg Alloy Doped with Sc, 2003)
Approximately 20-25 grams of Scandium are used annually in the US to produce high-intensity lighting. Usually found in stadiums and in commercial lighting kits, the element in combination with Mg produces a daylight effect useful in filming nighttime sports or events. Also used with mercury vapor lamps it creates a powerful artificial lighting source also implemented for night construction. Scandium is also present in laser applications such as commercial grade cutting and surgical lasers while future demand is expected to be in fuel cells. The radioactive isotope Sc-46 (85 day half-life) is used as a tracer in oil refinery cracking agents. (Scandium from Wikipedia, 2003)
Ashurst, which is a Canadian Aluminum company, has two issued patents for scandium alloys and five patents that are currently pending. The issued patents cover several specific alloy compositions mostly dealing in the realm of sports equipment. Ashurst maintains an active 34% ownership interest in the world’s largest and only known primary scandium mine, the Zhoti Vody, located in Ukraine. After the lifting of the Iron Curtain, these former Soviet deposits opened to world investment. The company’s participation in this venture is designed to ensure a consistent, long term supply of scandium for refinement in the West. At the present time, the mine employs approximately 900 people and produces a 2% aluminum-scandium master alloy exclusively for Ashurst and iron ore concentrate for sale in Eastern Europe as well as North and South America. (Scandium in Aluminum Alloys, 2003)
These patents may become more important as scandium becomes more useful to humans. It seems that humanity has entered a new age as the advantages of the left most d-block elements are exploited. Although scandium is scarce on earth, it continues to benefit people in many ways.