Hafnium Facts

Electrolytic hafnium, 22 grams. This piece is 1 x 2 x 3 cm. Element picture)

Hafnium is a lustrous, silvery-grey transition metal. Discovered in 1923, it was the next element with a stable core to be added to the periodic table (the last element was rhenium in 1925). Hafnium is named after the Latin word for Copenhagen: hafina. The element has some very important commercial uses, including applications in the nuclear energy industry, electronic equipment, ceramics, light bulbs and superalloy manufacturing.

Hafnium is rarely found free in nature, but is present in most zirconium minerals in concentrations up to 5%. In fact, the chemical properties of hafnium and zirconium are very similar, making it extremely difficult to separate the two elements. Most industrial hafnium is produced as a by-product of zirconium refining.

Hafnium is the 45th most abundant element on Earth, accounting for approximately 3.3 parts per million of the Earth's crust, according to Chemicool. Hafnium is very resistant to corrosion due to the formation of an oxide film on exposed surfaces. In fact, it is unaffected by water, air and all bases and acids except hydrogen fluoride.

Hafnium carbide (HfC) has the highest melting point of any known two-element compound at nearly 7034 degrees Fahrenheit (3890 degrees Celsius), and the compound hafnium nitride (HfN) also has a high melting point, according to Jefferson Laboratory , approximately 5981 degrees Fahrenheit (3305 degrees Celsius). According to Chemistry World, among the compounds of the three elements, the mixed carbide of tungsten and hafnium has the highest melting point of any known compound at 7,457 degrees Fahrenheit (4,125 degrees Celsius). Some other hafnium compounds include hafnium fluoride (HFF4), hafnium chloride (HfCl 4), and hafnium (HfO2). "KdSPE" is just the facts Atomic number (number of protons in the nucleus): 72 Atomic Symbol (Periodic Table of Elements): Hf Atomic Weight (average mass of an atom): 178.49 Density: 13.3 cubic centimeters of phase per chamber. Temperature: Solid Melting point: 4051 degrees Fahrenheit (2233 degrees Celsius) Boiling point: 8317 degrees Fahrenheit (4603 degrees Celsius) Number of isotopes (atoms of the same element have different numbers of neutrons): 32 Their half-lives are known, with mass numbers 154 to 185 being the most common The discovery of isotopes of: Hf-174, Hf-176, Hf-177, Hf-178, Hf-179 and Hf-180 (Andrei Marincas Shutterstock)

The existence of hafnium preceded its discovery decades ago has been predicted, reports Chemistry World. This element proved to be quite elusive, as it was nearly impossible to chemically distinguish it from the more common zirconium.

Hafnium was introduced in 1869 when Russian chemist and inventor Dimitri Mendeleev developed the periodic law (a pre-modern version of the periodic table). ) is still unknown. However, in his work, Mendeleev correctly predicted that there was an element with properties similar to, but heavier than, zirconium and titanium. In 1911,

French chemist Georges Urban, who had already discovered the rare earth element lutetium, believed he had finally discovered the missing element 72, and he began giving celtium its name, according to Chemicool. However, a few years later, his discovery turned out to be a combination of the already discovered lanthanides (15 metallic elements with atomic numbers 57 to 71 in the periodic table).

It is still unclear whether the missing element 72 is a transition metal or a rare earth metal, as it falls on the boundary between the two types of elements in the table. According to Chemistry World, chemists who thought it was a rare earth element conducted many fruitless studies in minerals containing rare earths.

However, new evidence from the fields of chemistry and physics supports the idea that element 72 will be a transition element. For example, scientists know that element 72 is lower on the periodic table than titanium and zirconium, both of which are known transition elements. In addition, according to Chemistry World, Danish physicist Niels Bohr, one of the founders of quantum theory, predicted based on its electronic structure that element 72 would be a transition metal in 1921< /p>

Bohr encouraged the Hungarian chemist Georg von Hevesi and the Dutch physicist Dirk Costerto, two young researchers at his institute at the time, to search for zirconium ores. 72 elements. Based on his quantum theory of atomic structure, Bohr knew that the new metal's chemical structure was similar to zirconium, so, according to Chemicool, there was a good chance that both elements would be found in the same ore.

Von Hevesy and Coster accepted Bohr's suggestion and began to use X-ray spectroscopy to study zirconium ores. They used Bohr's theory of how electrons fill shells and subshells within atoms to predict the difference between the X-ray spectra of the two elements, Chemical & Engineering News reported. This method eventually led to the discovery of hafnium in 1923. The discovery was one of only six remaining gaps in the periodic table at the time.

They named the new element after Bohr's hometown of Copenhagen (hafinain in Latin), using hafnium, which has significant corrosion resistance and is an excellent neutron absorber that can be used For nuclear submarines and nuclear reactor control rods, this is a key technology to maintain nuclear fission reactions. Control rods keep the fission chain reaction active but also prevent it from accelerating out of control.

Hafnium is used in electronic devices such as cathodes and capacitors, as well as in ceramics, photographic flashes, and light bulb filaments. Often alloyed with other metals such as titanium, iron, niobium and tantalum, hafnium is used as a getter in vacuum tubes, a substance that combines with trace amounts of gas in the tube and expels it, according to Jefferson Laboratory. For example, heat-resistant hafnium-rhodium alloys are used in aerospace applications such as space rocket engines.

The compound hafnium carbide has the highest melting point of any compound consisting of just two elements and can be used in production lines for high-temperature furnaces and kilns, according to Chemicool. Who knew? Hafnium is self-igniting (self-igniting) in powder form. British chemist Henry Moseley was a scientist who recognized that George Urban's element "celtium" was not the real element beneath zirconium. Unfortunately, World War I interrupted the young scientist's important research. Mosley dutifully joined the British Army's Royal Engineers and was killed by a sniper in 1915. His death led to a new British policy banning prominent scientists from combat. In 1925, Dutch chemists Anton Edward van Acker and Jan Hendrik de Boer proposed a method for producing high-purity hafnium. To do this, the scientists decomposed hafnium tetraiodide on a hot tungsten wire, resulting in a crystal rod of pure hafnium. This method is called the crystal rod method. The nuclear isomers of hafnium have long been controversial as potential weapons. In the hafnium debate, scientists debate whether the element can trigger a rapid release of energy. Although zirconium is chemically very similar to hafnium, it differs from it in that it absorbs neutrons very poorly. It is therefore important that zirconium is used in the outer layer of the fuel rods, where neutrons can move easily. In a recent study, an international team of researchers confirmed that Earth's first crust formed 4.5 billion years ago through chemical analysis of hafnium in rare meteorites. Researchers believe the meteorite originated from the asteroid Vesta after a giant impact sent rock fragments into Earth, according to a research news release in Science Daily. According to researchers, meteorites are fragments of the original material from which all planets are made.

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