Dubnium 化学特性,用途語,生産方法
解説
Db．原子番号105の元素．電子配置[Rn]5f 146d37s2(推定)の周期表5族元素．周期表でタンタルの下に位置する(エカタンタル)．1967年，旧ソビエトのドゥブナ原子核合同研究所で，310 cmサイクロトロンを用いて 22Ne を加速して 243Am を衝撃して質量数260，261の105番元素の原子をつくったと発表し，元素名としてニールスボーリウム Nsを提案した．1970年5月，カリフォルニア大学のA. Ghiorsoらは，HILAC(Heavy Ion Linear Accelerator)で 15N を84 MeV に加速して 249Cf を衝撃，半減期1.6 s の質量数261の105番元素原子を合成した．Ghiorsoらはドゥブナの方法も試みたが，105番元素合成に成功しなかった．GhiorsoらはO. Hahn(ハーン)にちなんでハーニウム Haと命名することを提案したが，IUPACは，両グループの業績を認めて105番元素については，地名ドゥブナによるドブニウムDbを勧告し，1997年に確定した．質量数255～269の同位体核種が知られており，267～269の核種は半減期がh単位，とくに268は32hとされる．室温で固体の銀白色または灰色の金属と考えられている．[CAS 53850-35-4]
森北出版「化学辞典（第2版）
物理的性質
Dubnium’s (Unp) most stable isotope, Db-268, is unstable with a half-life of 16 hours. Itcan change into lawrencium-254 by alpha decay or into rutherfordium-268 by electron capture.Both of these reactions occur through a series of decay processes and spontaneous fission(SF). Since so few atoms of unnilpentium (dubnium) are produced, and they have such a shorthalf-life, its melting point, boiling point, and density cannot be determined. In addition, itsvalence and oxidation state are also unknown.
同位体
There are a total of 15 isotopes of unnilpentium (dubnium). Their half-livesrange from 0.76 seconds (for Db-257) to 16 hours (for Db-268). All of them decay byspontaneous fission and alpha decay.
名前の由来
Unnilquadium follows the transitional naming system of IUPAC but
originally was named “hahnium” by the Berkeley group in honor of Otto Hahn, who discovered
nuclear fission. The American Chemical Society endorsed the name “hahnium”
for element 105, but as the Berkeley group continued its work and more isotopes of
105Unp were formed, the IUPAC changed the name “hahnium” to “dubnium” after the
city Dubna, Russia, where the first isotopes of unnilpentium were formed.
使用
There are no uses for unnilpentium (dubnium) except for research purposes.
定義
dubnium: Symbol Db. A radioactivetransactinide element; a.n. 105. Itwas first reported in 1967 by a groupat Dubna near Moscow and wasconfirmed in 1970 at Dubna and atBerkeley, California. It can be madeby bombarding californium–249 nucleiwith nitrogen–15 nuclei. Only afew atoms have ever been made.
危険性
The hazards of dubnium are similar to all radioactive heavy metals of the transactinideseries, but there is no threat to the public given that such a small amount of the element isproduced and exists.
Dubnium 上流と下流の製品情報
原材料
準備製品