베르켈리움
베르켈리움 · berkelium atom · berkelium ISO 9001：2015 REACH
식별자 및 물리적 특성
| CAS No. | 7440-40-6 |
|---|---|
| 분자식 | Bk |
| 평균 분자량 | 247.0703 g/mol |
| 단동위원소 질량 | 247.07031 g/mol |
| SMILES | [Bk] |
| InChIKey | PWVKJRSRVJTHTR-UHFFFAOYSA-N |
| PubChem CID | 23971 |
| ChEBI | CHEBI:33391 |
| DTXSID | DTXSID70225389 |
| 현지명 | 베르켈리움 |
화학 및 물리적 성질
| 극성 표면적 | 0 |
|---|---|
| 수소 결합 공여자 수 | 0 |
| 수소 결합 수용자 수 | 0 |
| 회전 가능 결합 수 | 0 |
| 무거운 원자 수 | 1 |
| 형식 전하 | 0 |
| 복잡도 | 0 |
| 물질 분류 | Physical/Radiation -> Radionuclides |
| Physical Description | A man-made radioactive metal with a melting point of 986 degrees CKnown isotopes have mass numbers of 240 and 242-251Bk-247 is the isotope with the longest half life[Merck Index # 1158] |
| 녹는점 | 986 ± 25° (Fahey)mp 1050° (Katz et al., loc. cit. vol. 2, p 1150) |
| 끓는 점 | ~2630℃ [KAT86] |
| 밀도 | (calc) 14.78d (calc) 13.25 |
| 물리적 상태 | 육각형 결정 |
| 색상 | hexagonal, hexane crystals, crystalline |
| Bulk Modulus | 52.0 GPa |
화학적 성질
The solubility properties of berkelium in its two oxidation states are entirely analogous to those of the actinide and lanthanide elements in the corresponding oxidation states. Thus in the tripositive state such compounds as the fluoride and the oxalate are insoluble in acid solution, and the tetrapositive state has such insoluble compounds as the iodate and phosphate in acid solution. The nitrate, sulfate, halides, perchlorate, and sulfide of both oxidation states are soluble. The first compound of berkelium of proven molecular structure was isolated in 1962 by Cunningham and Wallman. A small quantity (0.004 microgram) of berkelium (as berkelium-249) dioxide was used to determine structure by x-ray diffraction. Berkelium metal exists in two crystal modifications. Melting point of crystals has been estimated at 986 °C. The first production of berkelium required the solution to several problems in high energy physics. These included the necessity to synthesize the highly radioactive target elements used; safe handling procedures for the high levels of radioactivity encountered had to be developed; new systematics for predicting the modes of decay and half-lives of the still undiscovered isotopes were needed.
안전 및 규제
| 유해성 요약 | Most Important Radionuclide: Bk-247 Source: Nuclear reactors or particle acceleratorsHalf-Life: 1,400 years Specific Activity (mCi/gm): 1.1 Decay Mode: Alpha Internal Toxicity: Very High Annual Limit on Intake: 0.0000009 mCi Average Radiation Energy (MeV): Alpha 5.6Beta 0.061Gamma 0.11[Argonne] [See Glossary for references.] See Radiation, ionizing. |
|---|
용도
역사
Berkelium [CAS: 7440-40-6], the atomic number is 97 and the chemical symbol is Bk. The name is derived from Berkeley, the town in California where the element was first synthesized in 1949 by the American scientific team Stanley G. Thompson, Albert Ghiorso, and Glenn T. Seaborg at the University of California, Berkeley, CA., using the nuclear reaction 241Am(4He, 2n) 243Bk. It is the eighth element in the Actinide series of the elements and was named in analogy with Terbium (for Ytterby the town in Sweden whose mine produced the ore), which is the eighth element in the Lanthanide series of the elements. The longest half-life associated with this unstable element is 1400 year 247Bk. See also Berkelium.