Дармштадтий: Синтез, қасиеттері және атының тарихы

Darmstadtium is a synthetic chemical element; it has symbol Ds and atomic number 110. It is extremely radioactive: the most stable known isotope, darmstadtium 281, has a half life of approximately 14 seconds. Darmstadtium was first created in 1994 by the GSI Helmholtz Centre for Heavy Ion Research in the city of Darmstadt, Germany, after which it was named. In the periodic table, it is a d block transactinide element. It is a member of the 7th period and is placed in the group 10 elements, although no chemical experiments have yet been carried out to confirm that it behaves as the heavier homologue to platinum in group 10 as the eighth member of the 6d series of transition metals. Darmstadtium is calculated to have similar properties to its lighter homologues, nickel, palladium, and platinum.

Superheavy element

Darmstadtium was first discovered on November 9, 1994, at the Institute for Heavy Ion Research (Gesellschaft für Schwerionenforschung, GSI) in Darmstadt, Germany, by Peter Armbruster and Gottfried Münzenberg, under the direction of Sigurd Hofmann. The team bombarded a lead 208 target with accelerated nuclei of nickel 62 in a heavy ion accelerator and detected a single atom of the isotope darmstadtium 269:

Two more atoms followed on November 12 and 17. In the same series of experiments, the same team also carried out the reaction using heavier nickel 64 ions. During two runs, 9 atoms of were convincingly detected by correlation with known daughter decay properties:

Prior to this, there had been failed synthesis attempts in 1986–87 at the Joint Institute for Nuclear Research in Dubna (then in the Soviet Union) and in 1990 at the GSI. A 1995 attempt at the Lawrence Berkeley National Laboratory resulted in signs suggesting but not pointing conclusively at the discovery of a new isotope formed in the bombardment of with , and a similarly inconclusive 1994 attempt at the JINR showed signs of being produced from and Each team proposed its own name for element 110: the American team proposed hahnium after Otto Hahn in an attempt to resolve the controversy of naming element 105 (which they had long been suggesting this name for), the Russian team proposed becquerelium after Henri Becquerel, and the German team proposed darmstadtium after Darmstadt, the location of their institute. The IUPAC/IUPAP Joint Working Party (JWP) recognised the GSI team as discoverers in their 2001 report, giving them the right to suggest a name for the element.

Using Mendeleev's nomenclature for unnamed and undiscovered elements, darmstadtium should be known as eka platinum. In 1979, IUPAC published recommendations according to which the element was to be called ununnilium (with the corresponding symbol of Uun), a systematic element name as a placeholder, until the element was discovered (and the discovery then confirmed) and a permanent name was decided on. Although widely used in the chemical community on all levels, from chemistry classrooms to advanced textbooks, the recommendations were mostly ignored among scientists in the field, who called it "element 110", with the symbol of E110, (110) or even simply 110. The American team in 1997 proposed the name hahnium after Otto Hahn (previously this name had been used for element 105). The name darmstadtium (Ds) was suggested by the GSI team in honor of the city of Darmstadt, where the element was discovered. Policium had also been proposed as a joke due to the emergency telephone number in Germany being 1–1–0. The new name darmstadtium was officially recommended by IUPAC on August 16, 2003.

Darmstadtium has no stable or naturally occurring isotopes. Several radioactive isotopes have been synthesized in the laboratory, either by fusing two atoms or by observing the decay of heavier elements. Eleven different isotopes of darmstadtium have been reported with atomic masses 267, 269–271, 273, 275–277, and 279–281, although darmstadtium 267 is unconfirmed. Three darmstadtium isotopes, darmstadtium 270, darmstadtium 271, and darmstadtium 281, have known metastable states, although that of darmstadtium 281 is unconfirmed. Most of these decay predominantly through alpha decay, but some undergo spontaneous fission.

All darmstadtium isotopes are extremely unstable and radioactive; in general, the heavier isotopes are more stable than the lighter. The most stable known darmstadtium isotope, 281Ds, is also the heaviest known darmstadtium isotope; it has a half life of 14 seconds. The isotope 279Ds has a half life of 0.18 seconds, while the unconfirmed 281mDs has a half life of 0.9 seconds. The remaining isotopes and metastable states have half lives between 1 microsecond and 70 milliseconds. It also predicts that the undiscovered isotope 294Ds, which has a magic number of neutrons (184),

Other than nuclear properties, no properties of darmstadtium or its compounds have been measured; this is due to its extremely limited and expensive production and the fact that darmstadtium (and its parents) decays very quickly. Properties of darmstadtium metal remain unknown and only predictions are available.

Darmstadtium is the eighth member of the 6d series of transition metals, and should be much like the platinum group metals. Calculations on its ionization potentials and atomic and ionic radii are similar to that of its lighter homologue platinum, thus implying that darmstadtium's basic properties will resemble those of the other group 10 elements, nickel, palladium, and platinum. It is also expected to have the same octahedral molecular geometry as PtF6. Other predicted darmstadtium compounds are darmstadtium carbide (DsC) and darmstadtium tetrachloride (DsCl4), both of which are expected to behave like their lighter homologues.

Darmstadtium is expected to be a solid under normal conditions and to crystallize in the body centered cubic structure, unlike its lighter congeners which crystallize in the face centered cubic structure, because it is expected to have different electron charge densities from them. due to the short half lives of darmstadtium isotopes and a limited number of likely volatile compounds that could be studied on a very small scale. One of the few darmstadtium compounds that are likely to be sufficiently volatile is darmstadtium hexafluoride , as its lighter homologue platinum hexafluoride is volatile above 60 °C and therefore the analogous compound of darmstadtium might also be sufficiently volatile;

The more neutron rich darmstadtium isotopes are the most stable and indirect synthesis methods are not as favourable for chemical studies as direct synthesis methods. Following several unsuccessful attempts, 276Ds was produced in this reaction in 2022 and observed to have a half life less than a millisecond and a low yield, in agreement with predictions.