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105 Db (268)

Dubnium

Transition metal
Symbol Db
Atomic Number 105
Atomic Weight (268)
CAS Registry ID 53850-35-4
Group Name (none)
Period Number 7
Block d-block
State at STP Solid

Description

Sample of Dubnium โŒ• Enlarge Image

Dubnium is a synthetic element that is a transition metal. It is presumed to be a silver or metallic grey color in its, (presumed) solid state. Not must is known about his element, but it is predicted to have chemical properties similar to tantalum. Dubnium has an atomic weight of 268; the melting points and boiling points of this element are not currently known. Dubnium has no commercial use, nor any predicted commercial uses at this time.

Isolation

Dubnium does not occur in nature. This element must be synthesized instead using specialized equipment and processes; so far it has not been synthesized in any large amount.

Dubnium โŒ• Enlarge Image

Dubnium has been synthesized only a few times in its brief history. The complicated methods that are needed to produce dubnium, and the short half life of dubnium isotopes, have hindered scientific studies of this element. The first time that dubnium was synthesized was in 1967. At this time, researchers used americium and neon isotopes. The process involved bombarding the americium with neon to produce two isotopes of dubnium: isotope number 260 and isotope number 261. The second synthesis of dubnium occurred in 1970. At this time, researchers used nitrogen and californium. During this procedure, a target composed of californium was hit with a beam of nitrogen nuclei, (84 MeV), in a particle accelerator. An isotope of dubnium was produced, number 260, which had a half life of only 1.6 seconds. Dubnium is a radioactive element, but to what extent is not known. Further studies of the element are planned, but at this time no additional research has been conducted.

General

NameDubnium
SymbolDb
Number105
Chemical seriesTransition metal
Group5
Period7
Blockd
Appearanceunknown
Standard atomic weight(268) gยทmolโปยน
Electron configurationunknown
Electrons per shell2, 8, 18, 32, 32, 11, 2

Atomic Properties

Crystal structureunknown
Oxidation states
Electronegativity
Ionization energies
Atomic radius
Atomic radius (calc.)
Covalent radius
Van der Waals radius

Physical Properties

Phasepresumed solid
Density (near r.t.)
Liquid density at m.p.
Melting point
Boiling point
Critical point
Heat of fusion
Heat of vaporization
Heat capacity

Miscellaneous

Magnetic ordering
Electrical resistivity
Thermal conductivity
Thermal expansion
Speed of sound (thin rod)
Young's modulus
Shear modulus
Bulk modulus
Poisson ratio
Mohs hardness
Vickers hardness
Brinell hardness