Francium (Fr)
alkali-metalSolid
標準原子量
[223]電子配置
[Rn] 7s1融点
26.85 °C沸点
データなし密度
1870 kg/m³酸化数
+1電気陰性度（Pauling）
0.7第1イオン化エネルギー
4.072741 eV発見年
1939原子半径
データなし詳細
Francium is the heaviest known alkali metal and a member of group 1. All of its isotopes are radioactive, and the element occurs naturally only as fleeting decay products in uranium and thorium series minerals. Its chemistry is expected and partly observed to resemble an extremely electropositive form of caesium, dominated by the +1 oxidation state. Because the longest-lived isotope, ²²³Fr, has a half-life of only about 22 minutes, francium has no bulk technological role.
Francium was discovered in 1939 by Marguerite Perey, a physicist at the Curie Institute in Paris, France (Fig. IUPAC.87.1). 223Fr (with a half-life of 22 min) occurs naturally in uranium minerals as a result of actinium decay. However, it is estimated that no more than approximately 30 g of francium is present in the Earth’s crust at any time. Francium can be produced artificially for research by bombarding thorium with protons. Francium was named in honor of Perey’s home country, France [575], [576], [577]. Francium has no known isotopic applications outside of scientific research.
Francium was discovered by Marguerite Catherine Perey, a French chemist, in 1939 while analyzing actinium's decay sequence. Although considered a natural element, scientists estimate that there is no more than one ounce of francium in the earth's crust at one time. Since there is so little naturally occurring francium on earth, scientists must produce francium in order to study it. Francium can be produced by bombarding thorium with protons or by bombarding radium with neutrons. Francium's most stable isotope, francium-223, has a half-life of about 22 minutes. It decays into radium-223 through beta decay or into astatine-219 through alpha decay.
Discovered in 1939 by Mlle. Marguerite Perey of the Curie Institute, Paris. Francium, the heaviest known member of the alkali metals series, occurs as a result of an alpha disintegration of actinium. It can also be made artificially by bombarding thorium with protons. While it occurs naturally in uranium minerals, there is probably less than an ounce of francium at any time in the total crust of the earth. It has the highest equivalent weight of any element, and is the most unstable of the first 101 elements of the periodic system. Thirty-three isotopes of francium are recognized. The longest lived 223Fr (Ac, K), a daughter of 227Ac, has a half-life of 22 min. This is the only isotope of francium occurring in nature. Because all known isotopes of francium are highly unstable, knowledge of the chemical properties of this element comes from radiochemical techniques. No weighable quantity of the element has been prepared or isolated. The chemical properties of francium most resemble cesium.
No macroscopic sample of pure francium has been prepared, so its actual bulk appearance is unknown. By periodic trend it is predicted to be a very soft, silvery metallic solid, but this has not been directly observed.
Francium has no commercial or industrial use. Its practical use is confined to research with very small numbers of atoms, especially laser spectroscopy, tests of atomic structure theory in very heavy alkali atoms, and studies relevant to fundamental symmetry measurements. ²²³Fr and other isotopes can be generated from nuclear decay or accelerator reactions, but their short half-lives restrict experiments to specialized laboratories and prevent storage or shipment as ordinary material.
Due to the small amounts produced and its short half-life, there are currently no uses for francium outside of basic scientific research.
Francium chemistry is difficult to study because only tracer quantities exist at any time. The stable oxidation state is Fr⁺, and no well-characterized bulk compounds are known. Experiments and periodic trends indicate close analogy with caesium salts, including expected ionic compounds such as francium chloride, FrCl, and francium hydroxide, FrOH. Complexation and adsorption studies show behavior consistent with a large, weakly hydrated alkali-metal cation, but many thermodynamic values remain estimated or derived from trace-scale measurements.
See more information at the Francium compound page.
Francium is hazardous primarily because all isotopes are radioactive and decay rapidly, emitting radiation through isotope-specific decay chains. The element is not encountered outside nuclear or radiochemical settings. Chemical toxicity is poorly characterized and is of little practical importance compared with radiological dose, contamination control, and the hazards associated with its radioactive daughters.
Natural francium is continually produced in minute amounts by decay within uranium- and thorium-bearing materials and then quickly decays, so it does not accumulate as a persistent environmental contaminant. Its environmental chemistry is inferred to follow alkali-metal ion behavior in water and minerals, but the number of atoms present in nature is so small that it has no known biological or geochemical cycling role.
Francium has no commodity market, no commercial supply chain, and no demand outside research. It cannot be mined in meaningful quantity because natural inventories are extraordinarily small and transient. Research samples are made as needed, commonly by separating ²²³Fr from actinium decay sources or by producing neutron-deficient isotopes in accelerator experiments. The limiting factors are specialized facilities, radiochemical handling, rapid decay, and the need to conduct measurements immediately after production.
Formed by decay of actinium. Chemical properties similar to cesium. Decays to radium or astatine.
Francium is not a significant cosmic element. Any primordial francium would have decayed long ago, and present atoms arise only from ongoing radioactive decay or nuclear reactions. In stars, supernova debris, and planetary materials it is expected to be transient and extremely rare, with no stable isotope allowing accumulation over geological or astronomical time.
- Francium was discovered through its decay signature rather than from an isolated visible sample.
- Only trace radiochemical amounts can exist before most atoms decay away.
- ²²³Fr belongs to the actinium decay series.
- Francium is less well characterized experimentally than many synthetic elements with longer-lived isotopes.
- Its first ionization energy is among the lowest expected for any known element.
画像
性質
物理的性質
- 共有結合半径
- 260 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
- 348 pm 全元素のファンデルワールス半径を比較 →
- 密度
- 1870 kg/m³ 全元素の密度を比較 →
- 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
- 26.85 °C 全元素の融点を比較 →
- 結晶構造
- 体心立方構造 全元素の結晶構造を比較 →
化学的性質
- 電気陰性度（Pauling）
- 0.7 全元素の電気陰性度（Pauling）を比較 →
- 電気陰性度（Allen）
- 0.67
- 電子親和力
- 0.491 eV
- 第1イオン化エネルギー
- 4.072741 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
- 22.400077 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
- 33.500115 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
- 39.100135 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
- 50.000172 eV 全元素の第5イオン化エネルギーを比較 →
- 酸化数
- +1 全元素の酸化数を比較 →
- 価電子
- 1 全元素の価電子を比較 →
- 電子配置
- [Rn] 7s1
熱力学的性質
- 融解熱
- 0.02072861 eV 全元素の融解熱を比較 →
- 蒸発熱
- 0.67367985 eV 全元素の蒸発熱を比較 →
- 昇華熱
- 0.74622998 eV
- 原子化熱
- 0.74622998 eV
原子核
- 陽子数
- 87 全元素の陽子数を比較 →
- 中性子数
- 136 全元素の中性子数を比較 →
- 既知の同位体
- 37 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 →
- 質量数（最も安定な同位体）
- 223
- 最も安定な同位体
- Fr-223
- 発見年
- 1939
存在度
データなし
結晶構造
データなし
電子構造
- 各電子殻の電子数
- 2, 8, 18, 32, 18, 8, 1 全元素の各電子殻の電子数を比較 →
識別子
- CAS登録番号
- 7440-73-5 全元素のCAS登録番号を比較 →
- 項記号
- 2S1/2
- InChI
- InChI=1S/Fr
- InChI Key
- KLMCZVJOEAUDNE-UHFFFAOYSA-N
電子配置 測定値
Fr: 7s¹[Rn] 7s¹1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 5s² 5p⁶ 4f¹⁴ 5d¹⁰ 6s² 6p⁶ 7s¹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 |
|---|---|---|---|
| 233 放射性 | 233.05264 ± 0.00032 | データなし | 900 ms |
| 216 放射性 | 216.0031899 ± 0.0000045 | データなし | 700 ns |
| 203 放射性 | 203.0009407 ± 0.0000067 | データなし | 550 ms |
| 202 放射性 | 202.00332 ± 0.000055 | データなし | 372 ms |
| 215 放射性 | 215.0003418 ± 0.0000076 | データなし | 90 ns |
相／状態
理由: 融点（26.85 °C）より1.9 °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87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。
準位データの収録状況 ?
| イオン | 電荷 | 準位 |
|---|---|---|
| Fr I | 0 | 123 |
| Fr II | +1 | 2 |
| Fr III | +2 | 2 |
| Fr IV | +3 | 2 |
| Fr V | +4 | 2 |
| Fr VI | +5 | 2 |
| Fr VII | +6 | 2 |
| Fr VIII | +7 | 2 |
| Fr IX | +8 | 2 |
| Fr X | +9 | 2 |
結晶構造のデータはありません
結晶構造: bcc
イオン半径
| 電荷 | 配位 | スピン | 半径 |
|---|---|---|---|
| +1 | 6 | データなし | 180 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 | |
|---|---|---|---|---|---|
| 233 放射性 | 233.05264 ± 0.00032 | データなし | 900 ms | β- =100%β-n ? | |
| 216 放射性 | 216.0031899 ± 0.0000045 | データなし | 700 ns | α =100%β+ ? | |
| 203 放射性 | 203.0009407 ± 0.0000067 | データなし | 550 ms | α ≈100%β+ ? | |
| 202 放射性 | 202.00332 ± 0.000055 | データなし | 372 ms | α ≈100%β+ ? | |
| 215 放射性 | 215.0003418 ± 0.0000076 | データなし | 90 ns | α =100% |
スペクトル線
| 波長（nm） | 強度 | 電離段階 | 種類 | 遷移 | 精度 | 出典 | |
|---|---|---|---|---|---|---|---|
| 422.56552 nm | データなし | Fr I | emission | 7s 2S → 8p 2P* | 測定値 | NIST | |
| 432.53607 nm | データなし | Fr I | emission | 7s 2S → 8p 2P* | 測定値 | NIST | |
| 494.61573 nm | データなし | Fr I | emission | 7p 2P* → 20d 2D | 測定値 | NIST | |
| 495.91444 nm | データなし | Fr I | emission | 7p 2P* → 19d 2D | 測定値 | NIST | |
| 496.90308 nm | データなし | Fr I | emission | 7p 2P* → 20s 2S | 測定値 | NIST | |
| 497.49878 nm | データなし | Fr I | emission | 7p 2P* → 18d 2D | 測定値 | NIST | |
| 498.7192 nm | データなし | Fr I | emission | 7p 2P* → 19s 2S | 測定値 | NIST | |
| 499.45999 nm | データなし | Fr I | emission | 7p 2P* → 17d 2D | 測定値 | NIST | |
| 500.99176 nm | データなし | Fr I | emission | 7p 2P* → 18s 2S | 測定値 | NIST | |
| 501.92929 nm | データなし | Fr I | emission | 7p 2P* → 16d 2D | 測定値 | NIST | |
| 503.88964 nm | データなし | Fr I | emission | 7p 2P* → 17s 2S | 測定値 | NIST | |
| 505.10105 nm | データなし | Fr I | emission | 7p 2P* → 15d 2D | 測定値 | NIST | |
| 507.66912 nm | データなし | Fr I | emission | 7p 2P* → 16s 2S | 測定値 | NIST | |
| 509.27532 nm | データなし | Fr I | emission | 7p 2P* → 14d 2D | 測定値 | NIST | |
| 512.73622 nm | データなし | Fr I | emission | 7p 2P* → 15s 2S | 測定値 | NIST | |
| 514.93307 nm | データなし | Fr I | emission | 7p 2P* → 13d 2D | 測定値 | NIST | |
| 519.7664 nm | データなし | Fr I | emission | 7p 2P* → 14s 2S | 測定値 | NIST | |
| 522.89168 nm | データなし | Fr I | emission | 7p 2P* → 12d 2D | 測定値 | NIST | |
| 529.95916 nm | データなし | Fr I | emission | 7p 2P* → 13s 2S | 測定値 | NIST | |
| 534.64166 nm | データなし | Fr I | emission | 7p 2P* → 11d 2D | 測定値 | NIST | |
| 539.61762 nm | データなし | Fr I | emission | 7p 2P* → 20d 2D | 測定値 | NIST | |
| 539.6469 nm | データなし | Fr I | emission | 7p 2P* → 20d 2D | 測定値 | NIST | |
| 541.15779 nm | データなし | Fr I | emission | 7p 2P* → 19d 2D | 測定値 | NIST | |
| 541.19321 nm | データなし | Fr I | emission | 7p 2P* → 19d 2D | 測定値 | NIST | |
| 542.37083 nm | データなし | Fr I | emission | 7p 2P* → 20s 2S | 測定値 | NIST | |
| 543.03716 nm | データなし | Fr I | emission | 7p 2P* → 18d 2D | 測定値 | NIST | |
| 543.08061 nm | データなし | Fr I | emission | 7p 2P* → 18d 2D | 測定値 | NIST | |
| 544.53524 nm | データなし | Fr I | emission | 7p 2P* → 19s 2S | 測定値 | NIST | |
| 545.36417 nm | データなし | Fr I | emission | 7p 2P* → 17d 2D | 測定値 | NIST | |
| 545.4185 nm | データなし | Fr I | emission | 7p 2P* → 17d 2D | 測定値 | NIST | |
| 545.63748 nm | データなし | Fr I | emission | 7p 2P* → 12s 2S | 測定値 | NIST | |
| 547.24565 nm | データなし | Fr I | emission | 7p 2P* → 18s 2S | 測定値 | NIST | |
| 548.29545 nm | データなし | Fr I | emission | 7p 2P* → 16d 2D | 測定値 | NIST | |
| 548.36447 nm | データなし | Fr I | emission | 7p 2P* → 16d 2D | 測定値 | NIST | |
| 550.70515 nm | データなし | Fr I | emission | 7p 2P* → 17s 2S | 測定値 | NIST | |
| 552.06365 nm | データなし | Fr I | emission | 7p 2P* → 15d 2D | 測定値 | NIST | |
| 552.15244 nm | データなし | Fr I | emission | 7p 2P* → 15d 2D | 測定値 | NIST | |
| 553.17161 nm | データなし | Fr I | emission | 7p 2P* → 10d 2D | 測定値 | NIST | |
| 555.22268 nm | データなし | Fr I | emission | 7p 2P* → 16s 2S | 測定値 | NIST | |
| 557.02549 nm | データなし | Fr I | emission | 7p 2P* → 14d 2D | 測定値 | NIST | |
| 557.14445 nm | データなし | Fr I | emission | 7p 2P* → 14d 2D | 測定値 | NIST | |
| 561.28917 nm | データなし | Fr I | emission | 7p 2P* → 15s 2S | 測定値 | NIST | |
| 563.7589 nm | データなし | Fr I | emission | 7p 2P* → 13d 2D | 測定値 | NIST | |
| 563.92284 nm | データなし | Fr I | emission | 7p 2P* → 13d 2D | 測定値 | NIST | |
| 569.72475 nm | データなし | Fr I | emission | 7p 2P* → 14s 2S | 測定値 | NIST | |
| 571.87464 nm | データなし | Fr I | emission | 7p 2P* → 11s 2S | 測定値 | NIST | |
| 573.24676 nm | データなし | Fr I | emission | 7p 2P* → 12d 2D | 測定値 | NIST | |
| 573.48185 nm | データなし | Fr I | emission | 7p 2P* → 12d 2D | 測定値 | NIST | |
| 585.3491 nm | データなし | Fr I | emission | 7p 2P* → 9d 2D | 測定値 | NIST | |
| 587.29 nm | データなし | Fr I | emission | 7p 2P* → 11d 2D | 測定値 | NIST | |
| 587.64619 nm | データなし | Fr I | emission | 7p 2P* → 11d 2D | 測定値 | NIST | |
| 600.95745 nm | データなし | Fr I | emission | 7p 2P* → 12s 2S | 測定値 | NIST | |
| 609.52762 nm | データなし | Fr I | emission | 7p 2P* → 10d 2D | 測定値 | NIST | |
| 610.10952 nm | データなし | Fr I | emission | 7p 2P* → 10d 2D | 測定値 | NIST | |
| 618.5596 nm | データなし | Fr I | emission | 6d 2D → 20p 2P* | 測定値 | NIST | |
| 618.7831 nm | データなし | Fr I | emission | 6d 2D → 20p 2P* | 測定値 | NIST | |
| 621.0658 nm | データなし | Fr I | emission | 6d 2D → 19p 2P* | 測定値 | NIST | |
| 621.3414 nm | データなし | Fr I | emission | 6d 2D → 19p 2P* | 測定値 | NIST | |
| 621.98126 nm | データなし | Fr I | emission | 7p 2P* → 10s 2S | 測定値 | NIST | |
| 624.178 nm | データなし | Fr I | emission | 6d 2D → 18p 2P* | 測定値 | NIST | |
| 624.5235 nm | データなし | Fr I | emission | 6d 2D → 18p 2P* | 測定値 | NIST | |
| 626.3009 nm | データなし | Fr I | emission | 6d 2D → 20p 2P* | 測定値 | NIST | |
| 628.1118 nm | データなし | Fr I | emission | 6d 2D → 17p 2P* | 測定値 | NIST | |
| 628.5529 nm | データなし | Fr I | emission | 6d 2D → 17p 2P* | 測定値 | NIST | |
| 628.8704 nm | データなし | Fr I | emission | 6d 2D → 19p 2P* | 測定値 | NIST | |
| 632.0616 nm | データなし | Fr I | emission | 6d 2D → 18p 2P* | 測定値 | NIST | |
| 632.9403 nm | データなし | Fr I | emission | 7p 2P* → 11s 2S | 測定値 | NIST | |
| 633.1901 nm | データなし | Fr I | emission | 6d 2D → 16p 2P* | 測定値 | NIST | |
| 633.7661 nm | データなし | Fr I | emission | 6d 2D → 16p 2P* | 測定値 | NIST | |
| 636.0957 nm | データなし | Fr I | emission | 6d 2D → 17p 2P* | 測定値 | NIST | |
| 639.9141 nm | データなし | Fr I | emission | 6d 2D → 15p 2P* | 測定値 | NIST | |
| 640.6887 nm | データなし | Fr I | emission | 6d 2D → 15p 2P* | 測定値 | NIST | |
| 641.3044 nm | データなし | Fr I | emission | 6d 2D → 16p 2P* | 測定値 | NIST | |
| 648.2027 nm | データなし | Fr I | emission | 6d 2D → 15p 2P* | 測定値 | NIST | |
| 648.421 nm | データなし | Fr I | emission | 7p 2P* → 9d 2D | 測定値 | NIST | |
| 649.103 nm | データなし | Fr I | emission | 6d 2D → 14p 2P* | 測定値 | NIST | |
| 649.4876 nm | データなし | Fr I | emission | 7p 2P* → 9d 2D | 測定値 | NIST | |
| 650.1812 nm | データなし | Fr I | emission | 6d 2D → 14p 2P* | 測定値 | NIST | |
| 650.7242 nm | データなし | Fr I | emission | 7p 2P* → 8d 2D | 測定値 | NIST | |
| 657.633 nm | データなし | Fr I | emission | 6d 2D → 14p 2P* | 測定値 | NIST | |
| 662.174 nm | データなし | Fr I | emission | 6d 2D → 13p 2P* | 測定値 | NIST | |
| 663.746 nm | データなし | Fr I | emission | 6d 2D → 13p 2P* | 測定値 | NIST | |
| 671.054 nm | データなし | Fr I | emission | 6d 2D → 13p 2P* | 測定値 | NIST | |
| 681.787 nm | データなし | Fr I | emission | 6d 2D → 12p 2P* | 測定値 | NIST | |
| 684.222 nm | データなし | Fr I | emission | 6d 2D → 12p 2P* | 測定値 | NIST | |
| 691.204 nm | データなし | Fr I | emission | 6d 2D → 12p 2P* | 測定値 | NIST | |
| 694.8987 nm | データなし | Fr I | emission | 7p 2P* → 10s 2S | 測定値 | NIST | |
| 713.491 nm | データなし | Fr I | emission | 6d 2D → 11p 2P* | 測定値 | NIST | |
| 717.615 nm | データなし | Fr I | emission | 6d 2D → 11p 2P* | 測定値 | NIST | |
| 717.98664 nm | データなし | Fr I | emission | 7s 2S → 7p 2P* | 測定値 | NIST | |
| 723.811 nm | データなし | Fr I | emission | 6d 2D → 11p 2P* | 測定値 | NIST | |
| 728.5892 nm | データなし | Fr I | emission | 7p 2P* → 8d 2D | 測定値 | NIST | |
| 730.9713 nm | データなし | Fr I | emission | 7p 2P* → 8d 2D | 測定値 | NIST | |
| 744.1976 nm | データなし | Fr I | emission | 7p 2P* → 9s 2S | 測定値 | NIST |
詳細な性質
共有結合半径（詳細）
- 共有結合半径（Pyykkö）
- 223 pm
- 共有結合半径（Pyykkö、二重結合）
- 218 pm
ファンデルワールス半径
- Truhlar
- 348 pm
- UFF
- 490 pm
- MM3
- 364 pm
原子半径と金属半径
- 原子半径（Rahm）
- 258 pm
番号付けの尺度
- Mendeleev
- 6
- Pettifor
- 7
- Glawe
- 7
電気陰性度の尺度
- Ghosh
- 0
分極率と分散
- 双極子分極率
- 317.8 a.u.
- 双極子分極率（不確かさ）
- 2.4 a.u.
相転移と同素体
| 融点 | 294.15 K |
酸化数の分類
専門参考データ
結晶半径の詳細 (1)
| 電荷 | CN | スピン | rcrystal (pm) | 由来 |
|---|---|---|---|---|
| 1 | VI | 194 | Ahrens (1952) ionic radius, |
同位体の崩壊形式 (60)
| 同位体 | モード | 強度 |
|---|---|---|
| 197 | A | 100% |
| 198 | A | 100% |
| 199 | A | 100% |
| 199 | B+ | — |
| 200 | A | 100% |
| 200 | B+ | — |
| 200 | B+SF | — |
| 201 | A | 100% |
| 201 | B+ | — |
| 202 | A | 100% |
X線散乱因子 (516)
| エネルギー (eV) | f₁ | f₂ |
|---|---|---|
| 10 | — | 0.05044 |
| 10.1617 | — | 0.06059 |
| 10.3261 | — | 0.07277 |
| 10.4931 | — | 0.08938 |
| 10.6628 | — | 0.11712 |
| 10.8353 | — | 0.15347 |
| 11.0106 | — | 0.20109 |
| 11.1886 | — | 0.26349 |
| 11.3696 | — | 0.40321 |
| 11.5535 | — | 0.63759 |
追加データ
Estimated Crustal Abundance
The estimated element abundance in the earth's crust.
Not Applicable
参考文献 (1)
- [5] Francium https://education.jlab.org/itselemental/ele087.html
Estimated Oceanic Abundance
The estimated element abundance in the earth's oceans.
Not Applicable
参考文献 (1)
- [5] Francium https://education.jlab.org/itselemental/ele087.html
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 Francium.
The element property data was retrieved from publications.