Osmium (Os)
transition-metalSolid
標準原子量
190.23 u電子配置
[Xe] 6s2 4f14 5d6融点
3032.85 °C沸点
5011.85 °C密度
2.25872e+4 kg/m³酸化数
−4, −2, −1, 0, +1, +2, +3, +4, +5, +6, +7, +8電気陰性度（Pauling）
2.2第1イオン化エネルギー
8.43823 eV発見年
1803原子半径
130 pm詳細
Osmium is a very dense, hard, blue-white platinum-group metal. It is chemically noble in compact metallic form but is notable for forming volatile and highly toxic osmium tetroxide. Natural osmium occurs with other platinum-group elements in ultramafic ores and placer deposits, chiefly as alloys and sulfide-bearing mineral assemblages. Its rarity, difficult fabrication, and toxicity of some compounds limit its use despite unusual physical and chemical properties.
The metal is lustrous, bluish white, extremely hard, and brittle even at high temperatures. It has the highest melting point and the lowest vapor pressure of the platinum group. The metal is very difficult to fabricate, but the powdered or spongy metal slowly gives off osmium tetroxide, which as a powerful oxidizing agent and has a strong smell. The tetroxide is highly toxic, and boils at 130°C.
Density measurements show osmium to be a little more dense than iridium, and osmium is often cited as the heavier element. However, calculations of the density from the space lattice, which may be more reliable than these measurements, give a density of 22.65 for iridium compared to 22.61 for osmium. According to IUPAC, because of this apparent contradiction, no decision has been made as to which is heavier.
The name derives from the Greek osme for "smell" because of the sharp odor of its volatile oxide. Both osmium and iridium were discovered simultaneously in a crude platinum ore by the English chemist Smithson Tennant in 1803.
Osmium and iridium were discovered at the same time by the British chemist Smithson Tennant in 1803. Osmium and iridium were identified in the black residue remaining after dissolving platinum ore with aqua regia, a mixture of 25% nitric acid (HNO3) and 75% hydrochloric acid (HCl). Today, osmium is primarily recovered during the processing of platinum and nickel ores.
Discovered in 1803 by Tennant in the residue left when crude platinum is dissolved by aqua regia.
Pure osmium is a lustrous bluish white to blue-gray metal. It is extremely dense and hard but also brittle, so it is not readily shaped by ordinary metalworking. Finely divided osmium can oxidize slowly in air to form volatile osmium tetroxide.
Osmium metal has had limited historical use in very hard wear-resistant alloys, including early fountain-pen tips, instrument pivots, and electrical contacts, but most such uses have been replaced by other platinum-group alloys or tungsten materials. Osmium tetroxide, OsO₄, remains important in microscopy as a stain and fixative for unsaturated lipids and biological membranes. Osmium compounds are also used as specialized oxidation catalysts and reagents in organic synthesis, generally on small laboratory or fine-chemical scales.
Metallic osmium is hard, brittle and very difficult to make. Powdered osmium is easier to make but emits osmium tetroxide (OsO4) when it is exposed to the air. Unfortunately, osmium tetroxide smells bad and is very poisonous. Because of these problems, osmium is primarily used to make very hard alloys. Osmium alloys can be found in ball point pen tips, fountain pen tips, record player needles, electrical contacts and other devices where frictional wear must be minimized.
The tetroxide has been used to detect fingerprints and to stain fatty tissue for microscope slides. The metal is almost entirely used to produce very hard alloys with other metals of the platinum group for fountain pen tips, instrument pivots, phonograph needles, and electrical contacts.
Isotopes in Earth/Planetary Science
The isotope-amount ratio n(187Os)/n(186Os) in rocks can be transferred to fluids, such as magmas, groundwaters, rivers, and oceans. Variations in the inherited n(187Os)/n(186Os) ratios can provide a useful tracer for fluid sources and migration paths, including different layers of the Earth [301] G. Faure. Principles of Isotope Geology, 2nd Edition. p. 608. Wiley, New York (1986)., [504] A. Schersten. Re-Os, Pt-Os and Hf-W Isotopes and Tracing the Core in Mantle Melts, MantlePlumes.org (2014), Feb. 25; http://www.mantleplumes.org/Os-W.html., [516] A. D. Brandon, R. J. Walker. Earth. Planet. Sci. Lett.3-4 (232), 211 (2005)., [517] M. Sharma, G. J. Wasserburg, A. W. Hofmann, G. J. Chakrapani. Geochim. Cosmochim. Acta63 (23-24), 4005 (1999).. Meteorites and meteorite dust impacting the Earth have different osmium isotopic compositions than terrestrial rocks and sediments. As a result, n(187Os)/n(186Os)-ratio studies provide evidence of continuing extraterrestrial additions to the Earth over geologic time, as well as providing a method for prospecting in the sedimentary record for large meteorite impact events that may have affected life on Earth [518] F. S. Paquay, G. E. Ravizza, T. K. Dalai, B. Peucker-Ehrenbrink. Science320 (5873), 214 (2008)..
Isotopes in Geochronology
Some 187Os is radiogenic as a result of being formed by the beta decay of radioactive 187Re, which has a half-life of 4.16×1010 years. Variations in the isotope-amount ratio n(187Os)/n(186Os) and amount ratio n(187Re)/n(186Os) are used for geochronology; for example, variations in these ratios have been used to determine the ages of the Earth, Moon, and meteorites [301] G. Faure. Principles of Isotope Geology, 2nd Edition. p. 608. Wiley, New York (1986).. Kirk et al. [519] J. Kirk, J. Ruiz, J. Chesley, J. Walshe, G. England. Science297, 1856 (2002). measured rhenium-osmium isotopic abundances in gold and pyrites from conglomerates of the Central Rand Group of South Africa (Fig. IUPAC.76.1), which have produced over 48 000 metric tons of gold and have accounted for 40 percent of the world’s total historic production [520] H. E. Frimmel, W. E. L. Minter. Soc. Econ. Geol. Spec. Publ.9, 17 (2002).. The gold and rounded pyrites from the conglomerates yield an age of ~3.0×109 years. Kirk et al. find that this age is much older than that of the conglomerate, and they conclude that the gold is detrital (material wearing away by weathering or erosion) and was not deposited by later hydrothermal fluids.
Isotopes Used as a Source of Radioactive Isotope(s)
192Os can be used for the production of the medical radioisotope 195mPt via the 192Os (α, n) 195mPt reaction.
Osmium shows a wide range of oxidation states, from negative states in carbonyl complexes to the high +8 state. Osmium tetroxide, OsO₄, is the best-known compound; it is volatile, strongly oxidizing, and formed by oxidation of osmium metal or lower oxides. Osmium dioxide, OsO₂, is a stable dark oxide with rutile-type structure. Halide chemistry includes osmium tetrachloride, OsCl₄, and chloroosmate complexes such as hexachloroosmate(IV), [OsCl₆]²⁻. Organometallic and carbonyl complexes are important in coordination chemistry but are not bulk materials.
See more information at the Osmium compound page.
Compact osmium metal is relatively inert, but powders and sponges are hazardous because they can produce osmium tetroxide, OsO₄, in air. OsO₄ is highly toxic, volatile, and a strong oxidant; it can damage eyes, skin, and respiratory tissue at very low exposure levels. Osmium compounds should be treated as toxic laboratory chemicals. Natural osmium contains stable isotopes and is not a radiological hazard in ordinary material.
Concentrations in air as low as 107 g/m3 can cause lung congestion, skin damage, or eye damage. Exposure to osmium tetroxide should not exceed 0.0016 mg/m3 (8-hour time weighted average - 40-hour work week).
Osmium is a trace element in the crust and is commonly associated with platinum-group minerals in mafic and ultramafic rocks. It is highly particle-reactive in many natural settings and can be transported in detrital grains or bound to sulfides and organic-rich sediments. The rhenium-osmium isotope system is used to date some ores and sedimentary rocks. Environmental releases are normally very small, but soluble or volatile osmium compounds can be locally significant in laboratories and specialized industry.
Osmium is recovered as a minor by-product of platinum and nickel-copper ore processing rather than mined as a primary product. Separation from other platinum-group metals is technically demanding because of similar chemistry and because volatile osmium tetroxide, OsO₄, must be controlled. Demand is small and specialized, centered on laboratory reagents, catalysts, and limited alloy applications. Recycling occurs mainly through recovery of platinum-group metal residues rather than through a large independent osmium market. Substitution is common where hardness, corrosion resistance, or catalytic behavior can be supplied by iridium, ruthenium, platinum alloys, or non-precious materials.
Osmium occurs in iridosule and in platinum-bearing river sands in the Urals, North America, and South America. It is also found in the nickel-bearing ores of Sudbury, Ontario region along with other platinum metals. While the quantity of platinum metals in these ores is very small, the large tonnages of processed nickel ores make commercial recovery possible.
Osmium is a heavy element made mainly by neutron-capture processes in earlier generations of stars, with contributions from both rapid and slow neutron-capture pathways depending on isotope. It is rare in the solar system but enriched with other siderophile platinum-group elements in metallic phases. Its isotopic ratios are useful tracers in meteoritic and planetary differentiation studies.
- Osmium is usually cited as the densest naturally occurring element, very close to iridium.
- The name comes from the Greek word for smell, referring to the sharp odor of osmium tetroxide.
- Osmium tetroxide reacts with carbon-carbon double bonds, which underlies its use in staining lipids.
- Some osmiridium alloys occur naturally as hard metallic grains in placer deposits.
- The isotope ¹⁸⁷Os is the decay product of long-lived ¹⁸⁷Re.
画像
性質
物理的性質
- 原子半径（経験値）
- 130 pm 全元素の原子半径（経験値）を比較 →
- 共有結合半径
- 144 pm 全元素の共有結合半径を比較 →
- ファンデルワールス半径
- 216 pm 全元素のファンデルワールス半径を比較 →
- 金属半径
- 126 pm 全元素の金属半径を比較 →
- 密度
- 2.25872 × 104 kg/m³ 全元素の密度を比較 →
- モル体積
- 0.00843 L/mol
- 標準温度・圧力（STP）での相
- 固体 全元素の標準温度・圧力（STP）での相を比較 →
- 融点
- 3032.85 °C 全元素の融点を比較 →
- 沸点
- 5011.85 °C 全元素の沸点を比較 →
- 比熱容量
- 0.13 J/(g·K) 全元素の比熱容量を比較 →
- モル熱容量
- 24.7 J/(mol·K) 全元素のモル熱容量を比較 →
- 結晶構造
- 六方最密充填構造 全元素の結晶構造を比較 →
化学的性質
- 電気陰性度（Pauling）
- 2.2 全元素の電気陰性度（Pauling）を比較 →
- 電気陰性度（Allen）
- 1.65
- 電子親和力
- 1.1 eV
- 第1イオン化エネルギー
- 8.43823 eV 全元素の第1イオン化エネルギーを比較 →
- 第2イオン化エネルギー
- 17.000059 eV 全元素の第2イオン化エネルギーを比較 →
- 第3イオン化エネルギー
- 25.000086 eV 全元素の第3イオン化エネルギーを比較 →
- 第4イオン化エネルギー
- 41.000141 eV 全元素の第4イオン化エネルギーを比較 →
- 第5イオン化エネルギー
- 55.000189 eV 全元素の第5イオン化エネルギーを比較 →
- 酸化数
- −4, −2, −1, 0, +1, +2, +3, +4, +5, +6, +7, +8 全元素の酸化数を比較 →
- 価電子
- 8 全元素の価電子を比較 →
- 電子配置
- [Xe] 6s2 4f14 5d6
熱力学的性質
- 融解熱
- 0.32854848 eV 全元素の融解熱を比較 →
- 蒸発熱
- 6.425869 eV 全元素の蒸発熱を比較 →
- 昇華熱
- 8.187801 eV
- 原子化熱
- 8.187801 eV
- 原子化エンタルピー
- 8.156708 eV
原子核
- 陽子数
- 76 全元素の陽子数を比較 →
- 中性子数
- 116 全元素の中性子数を比較 →
- 既知の同位体
- 43 全元素の既知の同位体を比較 →
- 安定同位体
- 0 全元素の安定同位体を比較 →
- 最も安定な同位体
- Os-192
- 発見年
- 1803
存在度
- 存在度（地殻）
- 0.002 mg/kg 全元素の存在度（地殻）を比較 →
結晶構造
- 格子定数a
- 274 pm
電子構造
- 各電子殻の電子数
- 2, 8, 18, 32, 14, 2 全元素の各電子殻の電子数を比較 →
識別子
- CAS登録番号
- 7440-04-2 全元素のCAS登録番号を比較 →
- 項記号
- 5D4
- InChI
- InChI=1S/Os
- InChI Key
- SYQBFIAQOQZEGI-UHFFFAOYSA-N
電子配置 測定値
Os: 4f¹⁴ 5d⁶ 6s²[Xe] 4f¹⁴ 5d⁶ 6s²1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 5s² 5p⁶ 4f¹⁴ 5d⁶ 6s²原子モデル
同位体によって中性子数、質量、安定性は変わりますが、中性原子の電子配置は変わりません。
模式的な原子モデルです。実際の縮尺とは異なります。
原子の指紋
発光／吸収スペクトル
同位体分布
安定同位体はありません。
| 質量数 | 原子質量（u） | 天然存在比 | 半減期 |
|---|---|---|---|
| 167 放射性 | 166.971549 ± 0.000078 | データなし | 839 ms |
| 161 放射性 | 160.98903 ± 0.00043 | データなし | 640 us |
| 203 放射性 | 202.992195 ± 0.000429 | データなし | 300 ms |
| 166 放射性 | 165.972692 ± 0.00002 | データなし | 213 ms |
| 198 放射性 | 197.97441 ± 0.00021 | データなし | 125 秒 |
相／状態
理由: 融点（3032.85 °C）より3007.8 °C低い
模式図、実際の縮尺とは異なります
相転移点
相転移エネルギー
融点で1 molを融解させるのに必要なエネルギー
沸点で1 molを蒸発させるのに必要なエネルギー
昇華点で1 molを昇華させるのに必要なエネルギー
密度
標準条件下
標準条件下
原子スペクトル
全76件中10件を表示しています。 イオンの電荷の昇順で並べています。
スペクトル線データの収録状況 ?
| イオン | 電荷 | スペクトル線の総数 | 遷移確率 | 準位の表記 |
|---|---|---|---|---|
| Os I | 0 | 534 | 0 | 0 |
| Os II | +1 | 38 | 0 | 0 |
| Os III | +2 | 1061 | 1061 | 1061 |
準位データの収録状況 ?
| イオン | 電荷 | 準位 |
|---|---|---|
| Os I | 0 | 274 |
| Os II | +1 | 40 |
| Os III | +2 | 201 |
| Os IV | +3 | 2 |
| Os V | +4 | 2 |
| Os VI | +5 | 2 |
| Os VII | +6 | 2 |
| Os VIII | +7 | 2 |
| Os IX | +8 | 2 |
| Os X | +9 | 2 |
イオン半径
| 電荷 | 配位 | スピン | 半径 |
|---|---|---|---|
| +4 | 6 | データなし | 63 pm |
| +5 | 6 | データなし | 57.49999999999999 pm |
| +6 | 5 | データなし | 49 pm |
| +6 | 6 | データなし | 54.50000000000001 pm |
| +7 | 6 | データなし | 52.5 pm |
| +8 | 4 | データなし | 39 pm |
化合物
同位体 (5)
| 質量数 | 原子質量（u） | 天然存在比 | 半減期 | 崩壊形式 | |
|---|---|---|---|---|---|
| 167 放射性 | 166.971549 ± 0.000078 | データなし | 839 ms | α =51±0.4%β+ ? | |
| 161 放射性 | 160.98903 ± 0.00043 | データなし | 640 us | α ≈100% | |
| 203 放射性 | 202.992195 ± 0.000429 | データなし | 300 ms | β- ?β-n ? | |
| 166 放射性 | 165.972692 ± 0.00002 | データなし | 213 ms | α =83±0.4%β+ =17±0.4% | |
| 198 放射性 | 197.97441 ± 0.00021 | データなし | 125 秒 | β- =100% |
詳細な性質
共有結合半径（詳細）
- 共有結合半径（Pyykkö）
- 129 pm
- 共有結合半径（Pyykkö、二重結合）
- 116 pm
- 共有結合半径（Pyykkö、三重結合）
- 109 pm
ファンデルワールス半径
- Batsanov
- 200 pm
- Alvarez
- 248 pm
- UFF
- 312 pm
- MM3
- 235 pm
原子半径と金属半径
- 原子半径（Rahm）
- 244 pm
- 金属半径（C12）
- 135 pm
番号付けの尺度
- Mendeleev
- 61
- Pettifor
- 62
- Glawe
- 60
電気陰性度の尺度
- Ghosh
- 0
- Miedema
- 5
- Gunnarsson–Lundqvist
- 6
- Robles–Bartolotti
- 5
分極率と分散
- 双極子分極率
- 57 a.u.
- 双極子分極率（不確かさ）
- 3 a.u.
- C₆ (Gould–Bučko)
- 584 Ha·Bohr6
ミーデマパラメータ
- ミーデマモル体積
- 8.45 cm3/mol
- ミーデマ電子密度
- 6
供給リスクと経済性
- 生産集中度
- 60
- 相対供給リスク
- 8
- 埋蔵量の分布
- 95
- 政治的安定性（最大生産国）
- 44
- 政治的安定性（最大埋蔵国）
- 44
相転移と同素体
| 融点 | 3306.15 K |
| 沸点 | 5281.15 K |
酸化数の分類
専門参考データ
遮蔽定数 (14)
| n | 軌道 | σ |
|---|---|---|
| 1 | s | 1.4701 |
| 2 | p | 4.4502 |
| 2 | s | 19.8502 |
| 3 | d | 13.5253 |
| 3 | p | 21.7483 |
| 3 | s | 22.5727 |
| 4 | d | 37.142 |
| 4 | f | 38.8472 |
| 4 | p | 34.856 |
| 4 | s | 33.9048 |
結晶半径の詳細 (6)
| 電荷 | CN | スピン | rcrystal (pm) | 由来 |
|---|---|---|---|---|
| 4 | VI | 77 | from r^3 vs V plots, from metallic oxides, | |
| 5 | VI | 71.5 | estimated, | |
| 6 | V | 63 | ||
| 6 | VI | 68.5 | estimated, | |
| 7 | VI | 66.5 | estimated, | |
| 8 | IV | 53 |
同位体の崩壊形式 (58)
| 同位体 | モード | 強度 |
|---|---|---|
| 161 | A | 100% |
| 162 | A | 100% |
| 163 | A | 100% |
| 163 | B+ | — |
| 164 | A | 96% |
| 164 | B+ | — |
| 165 | A | 90% |
| 165 | B+ | 10% |
| 166 | A | 83% |
| 166 | B+ | 17% |
X線散乱因子 (516)
| エネルギー (eV) | f₁ | f₂ |
|---|---|---|
| 10 | — | 1.88117 |
| 10.1617 | — | 1.93789 |
| 10.3261 | — | 1.99632 |
| 10.4931 | — | 2.05652 |
| 10.6628 | — | 2.13032 |
| 10.8353 | — | 2.20812 |
| 11.0106 | — | 2.28877 |
| 11.1886 | — | 2.37237 |
| 11.3696 | — | 2.45796 |
| 11.5535 | — | 2.53755 |
追加データ
Estimated Crustal Abundance
The estimated element abundance in the earth's crust.
1.5×10-3 milligrams per kilogram
参考文献 (1)
Estimated Oceanic Abundance
The estimated element abundance in the earth's oceans.
Not Applicable
参考文献 (1)
Sources
Sources of this element.
Osmium occurs in iridosule and in platinum-bearing river sands in the Urals, North America, and South America. It is also found in the nickel-bearing ores of Sudbury, Ontario region along with other platinum metals. While the quantity of platinum metals in these ores is very small, the large tonnages of processed nickel ores make commercial recovery possible.
参考文献 (1)
- [6] Osmium https://periodic.lanl.gov/76.shtml
参考文献
(9)
Data deposited in or computed by PubChem
The half-life and atomic mass data was provided by the Atomic Mass Data Center at the International Atomic Energy Agency.
Element data are cited from the Atomic weights of the elements (an IUPAC Technical Report). The IUPAC periodic table of elements can be found at https://iupac.org/what-we-do/periodic-table-of-elements/. Additional information can be found within IUPAC publication doi:10.1515/pac-2015-0703 Copyright © 2020 International Union of Pure and Applied Chemistry.
The information are cited from Pure Appl. Chem. 2018; 90(12): 1833-2092, https://doi.org/10.1515/pac-2015-0703.
Thomas Jefferson National Accelerator Facility (Jefferson Lab) is one of 17 national laboratories funded by the U.S. Department of Energy. The lab's primary mission is to conduct basic research of the atom's nucleus using the lab's unique particle accelerator, known as the Continuous Electron Beam Accelerator Facility (CEBAF). For more information visit https://www.jlab.org/
The periodic table at the LANL (Los Alamos National Laboratory) contains basic element information together with the history, source, properties, use, handling and more. The provenance data may be found from the link under the source name.
The periodic table contains NIST's critically-evaluated data on atomic properties of the elements. The provenance data that include data for atomic spectroscopy, X-ray and gamma ray, radiation dosimetry, nuclear physics, and condensed matter physics may be found from the link under the source name. Ref: https://www.nist.gov/pml/atomic-spectra-database
This section provides all form of data related to element Osmium.
The element property data was retrieved from publications.