Darmstadtium (Ds)

• Element Symbol: Ds
• Atomic Number: 110
• Atomic Mass: [281]
• Group # in Periodic Table: 10
• Group Name: Transition metals
• Period in Periodic Table: 7
• Block of Periodic Table: d-block
• Discovered by: Sigurd Hofmann, Peter Armbruster, Gottfried Münzenberg (1994)

Darmstadtium is a synthetic element. Its symbol is Ds, and its atomic number is 110. In the periodic table, it belongs to the Group 10 elements. Darmstadtium was created on November 9, 1994, under the guidance and direction of Sigurd Hofmann, Peter Armbruster, Gottfried Münzenberg, Victor Ninov, and others at the GSI Helmholtz Centre for Heavy Ion Research near Darmstadt, Germany. They bombarded a lead-208 target with the nuclei of nickel-62 in a heavy ion accelerator. The team detected a single atom of the isotope darmstadtium-269.

The same team did more experiments using heavier nickel-64 ions. During two runs of this second experiment, they detected an atom of the isotope darmstadtium-271 by correlating its properties with the known decay properties of its daughter nucleus.

Many attempts to produce this element were made before 1994 at the Lawrence Berkeley National Laboratory (LBNL) in California and at the Joint Institute for Nuclear Research (JINR) in Dubna, Russia. These earlier experiments were done using both cold fusion and hot fusion processes. However, these earlier experiments did not successfully produce any atoms of darmstadtium. Thereafter, in a report of 2001, the Joint Working Party (JWP) that partnered the International Union of Pure and Applied Chemistry (IUPAC) and the International Union of Pure and Applied Physics (IUPAP) recognized the GSI team as the discoverer of this element. It was first known as eka-platinum. In 1979, the IUPAC published a paper that said that the element in the periodic table that would eventually be discovered by the GSI team in 1994 was to be called ununnilium, with symbol Uun. This name was given as a placeholder until a permanent name was chosen for the element and then subsequently confirmed by the IUPAC.

To honor the city Darmstadt, where the element was discovered, the GSI team proposed that the element be named darmstadtium (Ds). The IUPAC, on August 16, 2003, officially accepted the new name darmstadtium and added it to the Group 10 elements in the periodic table. Darmstadtium was the fourth element to be discovered at GSI.

Physical Properties

Darmstadtium has an atomic mass of 281 amu (atomic mass unit) and is a transition metal. It has 110 electrons. The electron shells of darmstadtium are 2, 8, 18, 32, 32, 17, and 1. Its electron configuration is [Rn] 5f¹⁴6d⁹7s¹. The predicted atomic radius is 132 picometers, and the covalent radius is estimated to be 128 picometers. Its crystal structure is unknown, although it is believed to be body-centered cubic. The element’s boiling and freezing points are also not known because the minute quantities that have been produced are so short-lived that many of darmstadtium’s properties cannot be determined. For the same reason, the element’s standard state—that is, its state at 298 kelvin (K)—is also unknown.

Darmstadtium has a molar volume of 196 cubic centimeters. Its thermal conductivity is 206 watts per meter kelvin, and its enthalpy of fusion is 203 kilojoules per mole. Its atomic number, 269, denotes that it is 269 times heavier than hydrogen. The element is presumed to be a metallic silvery-white/gray color, and its density near room temperature is theorized to be 34.8 grams per cubic centimeter.

Chemical Properties

Darmstadtium’s seven to eight isotopes have mass numbers from 267 to 281. Because the isotopes are not stable, they have short half-lives. Darmstadtium-281, with a half-life of 20 seconds, is the most stable isotope.

About 15 percent of the time, darmstadtium decays through alpha decay into hassium-277, but it decays via spontaneous fission the remaining 85 percent of the time. It has 110 protons and 159 neutrons. Chemically, darmstadtium is in the same group as nickel, palladium, and platinum (Group 10).

Darmstadtium has been observed as a decay product of copernicium. After copernicium has undergone alpha decay, four isotopes of the element revert to a darmstadtium nucleus with mass numbers between 273 and 281. No other element in the periodic table to date has been able to decay into darmstadtium, which is a superheavy element. It belongs to d-block and is a transactinide element.

Darmstadtium behaves like a heavier homologue of platinum in Group 10. No known isotope of darmstadtium has yet been observed to undergo beta decay.

Darmstadtium hexafluoride is predicted to have properties that are very similar to its lighter homologues, nickel and palladium. Isotopes of darmstadtium have been detected in the heavier metals. Like Group 10 elements, it can also be expected to have notable hardness and catalytic properties.

Several other compounds of darmstadtium are predicted, including darmstadtium carbide (DsC), darmstadtium chloride (DsCl), and darmstadtium tetrachloride (DsCl₄). These compounds are expected to behave like their lighter homologues. Darmstadtium is most stable in an aqueous solution according to predictions. Darmstadtium has isotopes of short half-lives and thus no chemical studies can be carried out on it.

Applications

Darmstadtium is not present in the environment or in the geosphere. It has no biological role, and thus there is no reason to study its health effects. It has no known commercial uses. Darmstadtium is used only for research purposes by researchers.

Bibliography

"Darmstadtium." Chemicool. Chemicool.com, n.d. Web. 18 Jan. 2016.

"Darmstadtium." Periodic Table. Royal Society of Chemistry, n.d. Web. 18 Jan. 2016.

"Darmstadtium (Ds)." Encyclopaedia Britannica Online. Encyclopaedia Britannica, Inc., n.d. Web. 18 Jan. 2016.

"Darmstadtium: The Essentials." WebElements. The University of Sheffield, n.d. Web. 18 Jan. 2016.

Encyclopedia of Earth and Physical Sciences. 2nd ed. Vol. 12. New York: Cavendish Square Publishing, 2005. Print.