Francium (Fr)
alkali-metalSolid
标准原子量
[223]电子排布
[Rn] 7s1熔点
26.85 °C沸点
暂无密度
1870 kg/m³氧化态
+1电负性（鲍林）
0.7第一电离能
4.072741 eV发现年份
1939原子半径
暂无详细信息
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.
图片
性质
物理性质
- 共价半径
- 260 pm 比较所有元素的共价半径 →
- 范德华半径
- 348 pm 比较所有元素的范德华半径 →
- 密度
- 1870 kg/m³ 比较所有元素的密度 →
- 标准温度和压力下的物相
- 固态 比较所有元素的标准温度和压力下的物相 →
- 熔点
- 26.85 °C 比较所有元素的熔点 →
- 晶体结构
- 体心立方 比较所有元素的晶体结构 →
化学性质
- 电负性（鲍林）
- 0.7 比较所有元素的电负性（鲍林） →
- 电负性（Allen）
- 0.67
- 电子亲和能
- 0.491 eV
- 第一电离能
- 4.072741 eV 比较所有元素的第一电离能 →
- 第二电离能
- 22.400077 eV 比较所有元素的第二电离能 →
- 第三电离能
- 33.500115 eV 比较所有元素的第三电离能 →
- 第四电离能
- 39.100135 eV 比较所有元素的第四电离能 →
- 第五电离能
- 50.000172 eV 比较所有元素的第五电离能 →
- 氧化态
- +1 比较所有元素的氧化态 →
- 价电子
- 1 比较所有元素的价电子 →
- 电子排布
- [Rn] 7s1
热力学性质
- 熔化热
- 0.02072861 eV 比较所有元素的熔化热 →
- 汽化热
- 0.67367985 eV 比较所有元素的汽化热 →
- 升华热
- 0.74622998 eV
- 原子化热
- 0.74622998 eV
核性质
- 质子
- 87 比较所有元素的质子 →
- 中子
- 136 比较所有元素的中子 →
- 已知同位素
- 37 比较所有元素的已知同位素 →
- 稳定同位素
- 0 比较所有元素的稳定同位素 →
- 质量数（最稳定同位素）
- 223
- 最稳定同位素
- Fr-223
- 发现年份
- 1939
丰度
暂无
晶体结构
暂无
电子结构
- 各电子层电子数
- 2, 8, 18, 32, 18, 8, 1 比较所有元素的各电子层电子数 →
标识符
- CAS登记号
- 7440-73-5 比较所有元素的CAS登记号 →
- 谱项符号
- 2S1/2
- InChI
- InChI=1S/Fr
- InChI Key
- KLMCZVJOEAUDNE-UHFFFAOYSA-N
电子排布 实测值
Fr: 7s¹[Rn] 7s¹1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 5s² 5p⁶ 4f¹⁴ 5d¹⁰ 6s² 6p⁶ 7s¹原子模型
不同同位素的中子数、质量和稳定性不同，但中性原子的电子排布不变。
原子模型示意图，未按比例绘制。
原子指纹
发射 / 吸收光谱
同位素分布
无稳定同位素。
| 质量数 | 原子质量（u） | 天然丰度 | 半衰期 |
|---|---|---|---|
| 233 放射性 | 233.05264 ± 0.00032 | 暂无 | 900 ms |
| 216 放射性 | 216.0031899 ± 0.0000045 | 暂无 | 700 ns |
| 203 放射性 | 203.0009407 ± 0.0000067 | 暂无 | 550 ms |
| 202 放射性 | 202.00332 ± 0.000055 | 暂无 | 372 ms |
| 215 放射性 | 215.0003418 ± 0.0000076 | 暂无 | 90 ns |
物相 / 状态
原因: 低于熔点（26.85 °C）1.9 °C
示意图，未按比例绘制
相变点
相变能
在熔点熔化1 mol物质所需的能量
在沸点汽化1 mol物质所需的能量
在升华点升华1 mol物质所需的能量
密度
标准条件下
标准条件下
原子光谱
已显示10项，共87项。 按离子电荷升序排列。
收录能级 ?
| 离子 | 电荷 | 能级 |
|---|---|---|
| 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 |
暂无晶体结构数据
晶体结构: bcc
离子半径
| 电荷 | 配位 | 自旋 | 半径 |
|---|---|---|---|
| +1 | 6 | 暂无 | 180 pm |
化合物
同位素 (5)
| 质量数 | 原子质量（u） | 天然丰度 | 半衰期 | 衰变方式 | |
|---|---|---|---|---|---|
| 233 放射性 | 233.05264 ± 0.00032 | 暂无 | 900 ms | β- =100%β-n ? | |
| 216 放射性 | 216.0031899 ± 0.0000045 | 暂无 | 700 ns | α =100%β+ ? | |
| 203 放射性 | 203.0009407 ± 0.0000067 | 暂无 | 550 ms | α ≈100%β+ ? | |
| 202 放射性 | 202.00332 ± 0.000055 | 暂无 | 372 ms | α ≈100%β+ ? | |
| 215 放射性 | 215.0003418 ± 0.0000076 | 暂无 | 90 ns | α =100% |
谱线
| 波长（nm） | 强度 | 电离级 | 类型 | 跃迁 | 准确度 | 来源 | |
|---|---|---|---|---|---|---|---|
| 422.56552 nm | 暂无 | Fr I | emission | 7s 2S → 8p 2P* | 实测值 | NIST | |
| 432.53607 nm | 暂无 | Fr I | emission | 7s 2S → 8p 2P* | 实测值 | NIST | |
| 494.61573 nm | 暂无 | Fr I | emission | 7p 2P* → 20d 2D | 实测值 | NIST | |
| 495.91444 nm | 暂无 | Fr I | emission | 7p 2P* → 19d 2D | 实测值 | NIST | |
| 496.90308 nm | 暂无 | Fr I | emission | 7p 2P* → 20s 2S | 实测值 | NIST | |
| 497.49878 nm | 暂无 | Fr I | emission | 7p 2P* → 18d 2D | 实测值 | NIST | |
| 498.7192 nm | 暂无 | Fr I | emission | 7p 2P* → 19s 2S | 实测值 | NIST | |
| 499.45999 nm | 暂无 | Fr I | emission | 7p 2P* → 17d 2D | 实测值 | NIST | |
| 500.99176 nm | 暂无 | Fr I | emission | 7p 2P* → 18s 2S | 实测值 | NIST | |
| 501.92929 nm | 暂无 | Fr I | emission | 7p 2P* → 16d 2D | 实测值 | NIST | |
| 503.88964 nm | 暂无 | Fr I | emission | 7p 2P* → 17s 2S | 实测值 | NIST | |
| 505.10105 nm | 暂无 | Fr I | emission | 7p 2P* → 15d 2D | 实测值 | NIST | |
| 507.66912 nm | 暂无 | Fr I | emission | 7p 2P* → 16s 2S | 实测值 | NIST | |
| 509.27532 nm | 暂无 | Fr I | emission | 7p 2P* → 14d 2D | 实测值 | NIST | |
| 512.73622 nm | 暂无 | Fr I | emission | 7p 2P* → 15s 2S | 实测值 | NIST | |
| 514.93307 nm | 暂无 | Fr I | emission | 7p 2P* → 13d 2D | 实测值 | NIST | |
| 519.7664 nm | 暂无 | Fr I | emission | 7p 2P* → 14s 2S | 实测值 | NIST | |
| 522.89168 nm | 暂无 | Fr I | emission | 7p 2P* → 12d 2D | 实测值 | NIST | |
| 529.95916 nm | 暂无 | Fr I | emission | 7p 2P* → 13s 2S | 实测值 | NIST | |
| 534.64166 nm | 暂无 | Fr I | emission | 7p 2P* → 11d 2D | 实测值 | NIST | |
| 539.61762 nm | 暂无 | Fr I | emission | 7p 2P* → 20d 2D | 实测值 | NIST | |
| 539.6469 nm | 暂无 | Fr I | emission | 7p 2P* → 20d 2D | 实测值 | NIST | |
| 541.15779 nm | 暂无 | Fr I | emission | 7p 2P* → 19d 2D | 实测值 | NIST | |
| 541.19321 nm | 暂无 | Fr I | emission | 7p 2P* → 19d 2D | 实测值 | NIST | |
| 542.37083 nm | 暂无 | Fr I | emission | 7p 2P* → 20s 2S | 实测值 | NIST | |
| 543.03716 nm | 暂无 | Fr I | emission | 7p 2P* → 18d 2D | 实测值 | NIST | |
| 543.08061 nm | 暂无 | Fr I | emission | 7p 2P* → 18d 2D | 实测值 | NIST | |
| 544.53524 nm | 暂无 | Fr I | emission | 7p 2P* → 19s 2S | 实测值 | NIST | |
| 545.36417 nm | 暂无 | Fr I | emission | 7p 2P* → 17d 2D | 实测值 | NIST | |
| 545.4185 nm | 暂无 | Fr I | emission | 7p 2P* → 17d 2D | 实测值 | NIST | |
| 545.63748 nm | 暂无 | Fr I | emission | 7p 2P* → 12s 2S | 实测值 | NIST | |
| 547.24565 nm | 暂无 | Fr I | emission | 7p 2P* → 18s 2S | 实测值 | NIST | |
| 548.29545 nm | 暂无 | Fr I | emission | 7p 2P* → 16d 2D | 实测值 | NIST | |
| 548.36447 nm | 暂无 | Fr I | emission | 7p 2P* → 16d 2D | 实测值 | NIST | |
| 550.70515 nm | 暂无 | Fr I | emission | 7p 2P* → 17s 2S | 实测值 | NIST | |
| 552.06365 nm | 暂无 | Fr I | emission | 7p 2P* → 15d 2D | 实测值 | NIST | |
| 552.15244 nm | 暂无 | Fr I | emission | 7p 2P* → 15d 2D | 实测值 | NIST | |
| 553.17161 nm | 暂无 | Fr I | emission | 7p 2P* → 10d 2D | 实测值 | NIST | |
| 555.22268 nm | 暂无 | Fr I | emission | 7p 2P* → 16s 2S | 实测值 | NIST | |
| 557.02549 nm | 暂无 | Fr I | emission | 7p 2P* → 14d 2D | 实测值 | NIST | |
| 557.14445 nm | 暂无 | Fr I | emission | 7p 2P* → 14d 2D | 实测值 | NIST | |
| 561.28917 nm | 暂无 | Fr I | emission | 7p 2P* → 15s 2S | 实测值 | NIST | |
| 563.7589 nm | 暂无 | Fr I | emission | 7p 2P* → 13d 2D | 实测值 | NIST | |
| 563.92284 nm | 暂无 | Fr I | emission | 7p 2P* → 13d 2D | 实测值 | NIST | |
| 569.72475 nm | 暂无 | Fr I | emission | 7p 2P* → 14s 2S | 实测值 | NIST | |
| 571.87464 nm | 暂无 | Fr I | emission | 7p 2P* → 11s 2S | 实测值 | NIST | |
| 573.24676 nm | 暂无 | Fr I | emission | 7p 2P* → 12d 2D | 实测值 | NIST | |
| 573.48185 nm | 暂无 | Fr I | emission | 7p 2P* → 12d 2D | 实测值 | NIST | |
| 585.3491 nm | 暂无 | Fr I | emission | 7p 2P* → 9d 2D | 实测值 | NIST | |
| 587.29 nm | 暂无 | Fr I | emission | 7p 2P* → 11d 2D | 实测值 | NIST | |
| 587.64619 nm | 暂无 | Fr I | emission | 7p 2P* → 11d 2D | 实测值 | NIST | |
| 600.95745 nm | 暂无 | Fr I | emission | 7p 2P* → 12s 2S | 实测值 | NIST | |
| 609.52762 nm | 暂无 | Fr I | emission | 7p 2P* → 10d 2D | 实测值 | NIST | |
| 610.10952 nm | 暂无 | Fr I | emission | 7p 2P* → 10d 2D | 实测值 | NIST | |
| 618.5596 nm | 暂无 | Fr I | emission | 6d 2D → 20p 2P* | 实测值 | NIST | |
| 618.7831 nm | 暂无 | Fr I | emission | 6d 2D → 20p 2P* | 实测值 | NIST | |
| 621.0658 nm | 暂无 | Fr I | emission | 6d 2D → 19p 2P* | 实测值 | NIST | |
| 621.3414 nm | 暂无 | Fr I | emission | 6d 2D → 19p 2P* | 实测值 | NIST | |
| 621.98126 nm | 暂无 | Fr I | emission | 7p 2P* → 10s 2S | 实测值 | NIST | |
| 624.178 nm | 暂无 | Fr I | emission | 6d 2D → 18p 2P* | 实测值 | NIST | |
| 624.5235 nm | 暂无 | Fr I | emission | 6d 2D → 18p 2P* | 实测值 | NIST | |
| 626.3009 nm | 暂无 | Fr I | emission | 6d 2D → 20p 2P* | 实测值 | NIST | |
| 628.1118 nm | 暂无 | Fr I | emission | 6d 2D → 17p 2P* | 实测值 | NIST | |
| 628.5529 nm | 暂无 | Fr I | emission | 6d 2D → 17p 2P* | 实测值 | NIST | |
| 628.8704 nm | 暂无 | Fr I | emission | 6d 2D → 19p 2P* | 实测值 | NIST | |
| 632.0616 nm | 暂无 | Fr I | emission | 6d 2D → 18p 2P* | 实测值 | NIST | |
| 632.9403 nm | 暂无 | Fr I | emission | 7p 2P* → 11s 2S | 实测值 | NIST | |
| 633.1901 nm | 暂无 | Fr I | emission | 6d 2D → 16p 2P* | 实测值 | NIST | |
| 633.7661 nm | 暂无 | Fr I | emission | 6d 2D → 16p 2P* | 实测值 | NIST | |
| 636.0957 nm | 暂无 | Fr I | emission | 6d 2D → 17p 2P* | 实测值 | NIST | |
| 639.9141 nm | 暂无 | Fr I | emission | 6d 2D → 15p 2P* | 实测值 | NIST | |
| 640.6887 nm | 暂无 | Fr I | emission | 6d 2D → 15p 2P* | 实测值 | NIST | |
| 641.3044 nm | 暂无 | Fr I | emission | 6d 2D → 16p 2P* | 实测值 | NIST | |
| 648.2027 nm | 暂无 | Fr I | emission | 6d 2D → 15p 2P* | 实测值 | NIST | |
| 648.421 nm | 暂无 | Fr I | emission | 7p 2P* → 9d 2D | 实测值 | NIST | |
| 649.103 nm | 暂无 | Fr I | emission | 6d 2D → 14p 2P* | 实测值 | NIST | |
| 649.4876 nm | 暂无 | Fr I | emission | 7p 2P* → 9d 2D | 实测值 | NIST | |
| 650.1812 nm | 暂无 | Fr I | emission | 6d 2D → 14p 2P* | 实测值 | NIST | |
| 650.7242 nm | 暂无 | Fr I | emission | 7p 2P* → 8d 2D | 实测值 | NIST | |
| 657.633 nm | 暂无 | Fr I | emission | 6d 2D → 14p 2P* | 实测值 | NIST | |
| 662.174 nm | 暂无 | Fr I | emission | 6d 2D → 13p 2P* | 实测值 | NIST | |
| 663.746 nm | 暂无 | Fr I | emission | 6d 2D → 13p 2P* | 实测值 | NIST | |
| 671.054 nm | 暂无 | Fr I | emission | 6d 2D → 13p 2P* | 实测值 | NIST | |
| 681.787 nm | 暂无 | Fr I | emission | 6d 2D → 12p 2P* | 实测值 | NIST | |
| 684.222 nm | 暂无 | Fr I | emission | 6d 2D → 12p 2P* | 实测值 | NIST | |
| 691.204 nm | 暂无 | Fr I | emission | 6d 2D → 12p 2P* | 实测值 | NIST | |
| 694.8987 nm | 暂无 | Fr I | emission | 7p 2P* → 10s 2S | 实测值 | NIST | |
| 713.491 nm | 暂无 | Fr I | emission | 6d 2D → 11p 2P* | 实测值 | NIST | |
| 717.615 nm | 暂无 | Fr I | emission | 6d 2D → 11p 2P* | 实测值 | NIST | |
| 717.98664 nm | 暂无 | Fr I | emission | 7s 2S → 7p 2P* | 实测值 | NIST | |
| 723.811 nm | 暂无 | Fr I | emission | 6d 2D → 11p 2P* | 实测值 | NIST | |
| 728.5892 nm | 暂无 | Fr I | emission | 7p 2P* → 8d 2D | 实测值 | NIST | |
| 730.9713 nm | 暂无 | Fr I | emission | 7p 2P* → 8d 2D | 实测值 | NIST | |
| 744.1976 nm | 暂无 | Fr I | emission | 7p 2P* → 9s 2S | 实测值 | NIST |
扩展性质
共价半径（扩展）
- 共价半径（Pyykkö）
- 223 pm
- 共价半径（Pyykkö，双键）
- 218 pm
范德华半径
- Truhlar
- 348 pm
- UFF
- 490 pm
- MM3
- 364 pm
原子半径与金属半径
- 原子半径（Rahm）
- 258 pm
编号标度
- Mendeleev
- 6
- Pettifor
- 7
- Glawe
- 7
电负性标度
- Ghosh
- 0
极化率与色散
- 偶极极化率
- 317.8 a.u.
- 偶极极化率（不确定度）
- 2.4 a.u.
相变与同素异形体
| 熔点 | 294.15 K |
氧化态分类
高级参考数据
晶体半径详情 (1)
| 电荷 | CN | 自旋 | rcrystal (pm) | 来源 |
|---|---|---|---|---|
| 1 | VI | 194 | Ahrens (1952) ionic radius, |
同位素衰变方式 (60)
| 同位素 | 模式 | 强度 |
|---|---|---|
| 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射线散射因子 (516)
| 能量 (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 |
补充数据
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.