Lanthanum (La)
lanthanideSolid
मानक परमाणु भार
138.90547 uइलेक्ट्रॉन विन्यास
[Xe] 6s2 5d1गलनांक
917.85 °Cक्वथनांक
3463.85 °Cघनत्व
6150 kg/m³ऑक्सीकरण अवस्थाएँ
0, +1, +2, +3विद्युतऋणात्मकता (पॉलिंग)
1.1आयनन ऊर्जा (प्रथम)
5.5769 eVखोज का वर्ष
1839परमाणु त्रिज्या
195 pmविवरण
Lanthanum is the first element of the lanthanide series by common convention, although its 4f shell is empty in the neutral atom. It is a soft, reactive rare-earth metal that occurs with other light rare earths in minerals such as monazite and bastnäsite. Its chemistry is dominated by the large La³⁺ ion, which gives mostly colorless, strongly ionic compounds. Lanthanum is important in optical glass, catalysts, battery alloys, and high-temperature ceramic materials.
Lanthanum is silvery white, malleable, ductile, and soft enough to be cut with a knife. It is one of the most reactive of the rare-earth metals. It oxidizes rapidly when exposed to air. Cold water attacks lanthanum slowly, while hot water attacks it much more rapidly.
The metal reacts directly with elemental carbon, nitrogen, boron, selenium, silicon, phosphorus, sulfur, and with halogens.
At 310°C, lanthanum changes from a hexagonal to a face-centered cubic structure, and at 865°C it again transforms into a body-centered cubic structure.
The name derives from the Greek lanthanein for "to be hidden" or "to escape notice" because it hid in cerium ore and was difficult to separate from that rare earth mineral. Lanthanum was discovered by the Swedish surgeon and chemist Carl-Gustav Mosander in 1839. In 1842, Mosander separated his lanthanium sample into two oxides; for one of these he retained the name lanthanum and for the other he gave the name didymium (or twin).
Lanthanum was discovered by Carl Gustaf Mosander, a Swedish chemist, in 1839. Mosander was searching for impurities he believed existed within samples of cerium. He treated cerium nitrate (Ce(NO3)3) with dilute nitric acid (HNO3) and found a new substance he named lanthana (La2O3). Roughly 0.0018% of the earth's crust is composed of lanthanum. Today, lanthanum is primarily obtained through an ion exchange process from monazite sand ((Ce, La, Th, Nd, Y)PO4), a material rich in rare earth elements that can contain as much as 25% lanthanum.
From the Greek word lanthanein, to escape notice. Mosander in 1839 extracted lanthana from impure cerium nitrate and recognized the new element.
Lanthanum was isolated in relatively pure form in 1923. Iron exchange and solvent extraction techniques have led to much easier isolation of the so-called "rare-earth" elements.
Pure lanthanum is a silvery-white, soft metal that can be cut with a knife when freshly prepared. It tarnishes rapidly in air, forming oxide and hydroxide films, and reacts slowly with cold water but more rapidly when finely divided or heated.
Lanthanum is used in high-refractive-index optical glasses for camera lenses, microscopes, and other precision optics. Mixed rare-earth metal rich in lanthanum has been used in lighter flints and spark-producing alloys. Lanthanum-containing nickel-metal hydride battery alloys store hydrogen reversibly. Lanthanum compounds are also used in fluid catalytic cracking catalysts, ceramic capacitors and dielectric materials, phosphors, and as additives in tungsten electrodes and specialty steels.
Lanthanum is one of the rare earth elements used to make carbon arc lights which are used in the motion picture industry for studio lighting and projector lights. Lanthanum also makes up about 25% of Misch metal, a material that is used to make flints for lighters. Lanthana (La2O3) is used to make the glass used in camera lenses and in other special glasses.
Rare-earth compounds containing lanthanum are extensively used in carbon lighting applications, especially by the motion picture industry for studio lighting and projection. This application consumes about 25 percent of the rare-earth compounds produced. La2O3 improves the alkali resistance of glass, and is used in making special optical glasses. Small amounts of lanthanum, as an additive, can be used to produce nodular cast iron.
There is current interest in hydrogen sponge alloys containing lanthanum. These alloys take up to 400 times their own volume of hydrogen gas, and the process is reversible. Every time they take up the gas, heat energy is released; therefore these alloys have possibilities in an energy conservation system.
Isotopes in Earth/Planetary Science
Studies have shown that 138La (with a half-life of 1.06×1011 years) can be used along with 138Ce and 136Ce to measure time elapsed from a supernova explosion producing large numbers of neutrinos [415] T. Hayakawa, T. Shizuma, T. Kajino, K. Ogawa, H. Nakada. Am. Phys. Soc.77, (2008)..
Isotopes in Geochronology
138La decays to 138Ce and 138Ba, respectively, by beta decay with a half-life of 1.06×1011 years and by electron capture with a half-life of 1.56×1011 years. The isotope-amount ratio n(138Ce)/n(142Ce) has been used for dating rocks on long time scales (billions of years) and as a chemical tracer in geochemistry [416] T. Hayashi, M. Tanimizu, T. Tanaka. Precambrian Res.135, 345 (2004).. The increase in radiogenic 138Ba in rocks enriched in rare earth elements, such as allanite, enables one to determine the age of such rocks (Fig. IUPAC.57.1) [417] S. Nakai, H. Shimizu, A. Masuda. Nature320, 433 (1986)..
Isotopes Used as a Source of Radioactive Isotope(s)
139La is used for the production of the medical radioisotope 139Ce via the 139La (p, n) 139Ce reaction [418] H. Aglan, S. A. Kandil, H. A. Hanafi, M. A. Mousa, Z. A. Saleh. J. Radioanal. Nucl. Chem.280, 533 (2009)..
Lanthanum almost exclusively forms compounds in the +3 oxidation state. Lanthanum oxide (La₂O₃) is a basic oxide used in optical glass and ceramics and readily absorbs moisture and CO₂ from air. Lanthanum chloride (LaCl₃), lanthanum nitrate (La(NO₃)₃), and lanthanum carbonate (La₂(CO₃)₃) are common salts of the La³⁺ ion. Lanthanum hexaboride (LaB₆) is a refractory conductor valued as an electron-emission material. Lanthanum strontium manganite, often written La₁₋ₓSrₓMnO₃, is important in oxide electronics and solid oxide fuel-cell cathodes.
See more information at the Lanthanum compound page.
Metallic lanthanum dust and turnings are flammable, and the metal reacts with moisture to release hydrogen. Soluble lanthanum salts can irritate skin, eyes, and the respiratory tract and may disturb calcium-related biological processes at sufficient exposure. Lanthanum has no established essential biological role. Natural lanthanum is effectively stable; radiological risk normally comes from associated thorium or uranium in ores, not from lanthanum itself.
Lanthanum and its compounds have a low to moderate acute toxicity rating; therefore, care should be taken in handling them.
Lanthanum occurs dispersed in the crust with other rare-earth elements and is concentrated mainly in phosphate and carbonate minerals. Weathering releases La³⁺ into soils and waters, where it tends to bind strongly to clays, organic matter, phosphates, and carbonates rather than remain highly mobile. Mining and processing can increase local rare-earth, acid, fluoride, and radionuclide burdens, depending on ore type and waste management.
Lanthanum is obtained chiefly as a co-product of rare-earth mining and separation, especially from bastnäsite and monazite concentrates. Separation relies on solvent extraction or ion-exchange processes because neighboring rare earths have very similar chemistry. It is one of the more abundant and lower-cost rare earths, but supply depends on integrated rare-earth processing capacity and demand for other elements in the same ores. Recycling occurs in limited streams such as nickel-metal hydride batteries and some catalysts, while optical glass and ceramics are less commonly recovered for lanthanum content.
Lanthanum is found in rare-earth minerals such as cerite, monazite, allanite, and bastnasite. Monazite and bastnasite are principal ores in which lanthanum occurs in percentages up to 25 percent and 38 percent respectively. Misch metal, used in making lighter flints, contains about 25 percent lanthanum.
The availability of lanthanum and other rare earths has improved greatly in recent years. The metal can be produced by reducing the anhydrous fluoride with calcium.
Lanthanum is an odd-atomic-number heavy element made mainly by neutron-capture processes followed by radioactive decay in earlier generations of stars. It is far less abundant cosmically than iron-group elements but is measurable in the Sun, meteorites, and many old stars. Its abundance pattern helps distinguish slow and rapid neutron-capture contributions in stellar material.
- Lanthanum metal expands when it solidifies, an uncommon behavior among metals.
- The name comes from Greek lanthanein, meaning to lie hidden, because it was found concealed in cerium minerals.
- La³⁺ is diamagnetic because it has no 4f electrons.
- Lanthanum hexaboride cathodes can emit electrons efficiently at high temperature.
- Lanthanum carbonate is used as a phosphate binder in some medical applications.
चित्र
गुण
भौतिक
- परमाणु त्रिज्या (आनुभविक)
- 195 pm सभी तत्वों की परमाणु त्रिज्या (आनुभविक) की तुलना करें →
- सहसंयोजक त्रिज्या
- 207 pm सभी तत्वों की सहसंयोजक त्रिज्या की तुलना करें →
- वान डर वाल्स त्रिज्या
- 240 pm सभी तत्वों की वान डर वाल्स त्रिज्या की तुलना करें →
- धात्विक त्रिज्या
- 169 pm सभी तत्वों की धात्विक त्रिज्या की तुलना करें →
- घनत्व
- 6150 kg/m³ सभी तत्वों की घनत्व की तुलना करें →
- मोलर आयतन
- 0.0225 L/mol
- STP पर प्रावस्था
- ठोस सभी तत्वों की STP पर प्रावस्था की तुलना करें →
- गलनांक
- 917.85 °C सभी तत्वों की गलनांक की तुलना करें →
- क्वथनांक
- 3463.85 °C सभी तत्वों की क्वथनांक की तुलना करें →
- तापीय चालकता
- 13.4 W/(m·K) सभी तत्वों की तापीय चालकता की तुलना करें →
- विशिष्ट ऊष्मा धारिता
- 0.195 J/(g·K) सभी तत्वों की विशिष्ट ऊष्मा धारिता की तुलना करें →
- मोलर ऊष्मा धारिता
- 27.11 J/(mol·K) सभी तत्वों की मोलर ऊष्मा धारिता की तुलना करें →
- क्रिस्टल संरचना
- षट्कोणीय सघन संकुलित सभी तत्वों की क्रिस्टल संरचना की तुलना करें →
रासायनिक
- विद्युतऋणात्मकता (पॉलिंग)
- 1.1 सभी तत्वों की विद्युतऋणात्मकता (पॉलिंग) की तुलना करें →
- इलेक्ट्रॉन बंधुता
- 0.47 eV
- आयनन ऊर्जा (प्रथम)
- 5.5769 eV सभी तत्वों की आयनन ऊर्जा (प्रथम) की तुलना करें →
- आयनन ऊर्जा (द्वितीय)
- 11.184999 eV सभी तत्वों की आयनन ऊर्जा (द्वितीय) की तुलना करें →
- आयनन ऊर्जा (तृतीय)
- 19.177366 eV सभी तत्वों की आयनन ऊर्जा (तृतीय) की तुलना करें →
- आयनन ऊर्जा (चतुर्थ)
- 49.950172 eV सभी तत्वों की आयनन ऊर्जा (चतुर्थ) की तुलना करें →
- आयनन ऊर्जा (पंचम)
- 61.600212 eV सभी तत्वों की आयनन ऊर्जा (पंचम) की तुलना करें →
- ऑक्सीकरण अवस्थाएँ
- 0, +1, +2, +3 सभी तत्वों की ऑक्सीकरण अवस्थाएँ की तुलना करें →
- संयोजकता इलेक्ट्रॉन
- 3 सभी तत्वों की संयोजकता इलेक्ट्रॉन की तुलना करें →
- इलेक्ट्रॉन विन्यास
- [Xe] 6s2 5d1
ऊष्मागतिक
- गलन ऊष्मा
- 0.06425869 eV सभी तत्वों की गलन ऊष्मा की तुलना करें →
- वाष्पन ऊष्मा
- 4.145722 eV सभी तत्वों की वाष्पन ऊष्मा की तुलना करें →
- ऊर्ध्वपातन ऊष्मा
- 4.467016 eV
- परमाणुकरण ऊष्मा
- 4.467016 eV
- परमाणुकरण एन्थैल्पी
- 4.467016 eV
नाभिकीय
- प्रोटॉन
- 57 सभी तत्वों की प्रोटॉन की तुलना करें →
- न्यूट्रॉन
- 82 सभी तत्वों की न्यूट्रॉन की तुलना करें →
- ज्ञात समस्थानिक
- 42 सभी तत्वों की ज्ञात समस्थानिक की तुलना करें →
- स्थिर समस्थानिक
- 1 सभी तत्वों की स्थिर समस्थानिक की तुलना करें →
- सबसे स्थिर समस्थानिक
- La-139
- खोज का वर्ष
- 1839
प्रचुरता
- प्रचुरता (भूपर्पटी)
- 39 mg/kg सभी तत्वों की प्रचुरता (भूपर्पटी) की तुलना करें →
- प्रचुरता (महासागर)
- 3.4 × 10−6 mg/L सभी तत्वों की प्रचुरता (महासागर) की तुलना करें →
क्रिस्टल संरचना
- जालक स्थिरांक a
- 375 pm
इलेक्ट्रॉनिक संरचना
- प्रति कोश इलेक्ट्रॉन
- 2, 8, 18, 18, 9, 2 सभी तत्वों की प्रति कोश इलेक्ट्रॉन की तुलना करें →
पहचानकर्ता
- CAS संख्या
- 7439-91-0 सभी तत्वों की CAS संख्या की तुलना करें →
- टर्म प्रतीक
- 2D3/2
- InChI
- InChI=1S/La
- InChI कुंजी
- FZLIPJUXYLNCLC-UHFFFAOYSA-N
इलेक्ट्रॉन विन्यास मापित
La: 5d¹ 6s²[Xe] 5d¹ 6s²1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 5s² 5p⁶ 5d¹ 6s²परमाणु मॉडल
समस्थानिक न्यूट्रॉन की संख्या, द्रव्यमान और स्थिरता बदलते हैं — उदासीन परमाणु का इलेक्ट्रॉन विन्यास नहीं।
सांकेतिक परमाणु मॉडल, वास्तविक अनुपात में नहीं।
परमाणु पहचान-चिह्न
उत्सर्जन / अवशोषण स्पेक्ट्रम
समस्थानिक वितरण
| द्रव्यमान संख्या | परमाणु द्रव्यमान (u) | प्राकृतिक प्रचुरता | अर्धायु |
|---|---|---|---|
| 139 स्थिर | 138.9063563 ± 0.0000024 | 99.9112% | स्थिर |
प्रावस्था / अवस्था
कारण: गलनांक (917.85 °C) से 892.9 °C कम
सांकेतिक, वास्तविक अनुपात में नहीं
प्रावस्था संक्रमण बिंदु
संक्रमण ऊर्जाएँ
गलनांक पर 1 mol को पिघलाने के लिए आवश्यक ऊर्जा
क्वथनांक पर 1 mol को वाष्पित करने के लिए आवश्यक ऊर्जा
ऊर्ध्वपातनांक पर 1 mol के ऊर्ध्वपातन के लिए आवश्यक ऊर्जा
घनत्व
मानक परिस्थितियों में
मानक परिस्थितियों में
परमाणु स्पेक्ट्रम
57 में से 10 दिखाए जा रहे हैं। आयन के आवेश के अनुसार आरोही क्रम में व्यवस्थित।
उपलब्ध स्पेक्ट्रमी रेखा डेटा ?
| आयन | आवेश | कुल रेखाएँ | संक्रमण प्रायिकताएँ | स्तर पदनाम |
|---|---|---|---|---|
| La I | 0 | 393 | 315 | 393 |
| La II | +1 | 273 | 84 | 273 |
| La III | +2 | 122 | 0 | 0 |
| La IV | +3 | 87 | 0 | 0 |
| La V | +4 | 42 | 0 | 0 |
उपलब्ध ऊर्जा स्तर डेटा ?
| आयन | आवेश | स्तर |
|---|---|---|
| La I | 0 | 343 |
| La II | +1 | 119 |
| La III | +2 | 42 |
| La IV | +3 | 52 |
| La V | +4 | 37 |
| La VI | +5 | 2 |
| La VII | +6 | 2 |
| La VIII | +7 | 2 |
| La IX | +8 | 2 |
| La X | +9 | 2 |
आयनिक त्रिज्याएँ
| आवेश | उपसहसंयोजन | प्रचक्रण | त्रिज्या |
|---|---|---|---|
| +3 | 6 | उपलब्ध नहीं | 103.2 pm |
| +3 | 7 | उपलब्ध नहीं | 110.00000000000001 pm |
| +3 | 8 | उपलब्ध नहीं | 115.99999999999999 pm |
| +3 | 9 | उपलब्ध नहीं | 121.6 pm |
| +3 | 10 | उपलब्ध नहीं | 127 pm |
| +3 | 12 | उपलब्ध नहीं | 136 pm |
यौगिक
समस्थानिक (1)
Natural lanthanum is a mixture of two stable isotopes, 138La and 139La. Twenty three other radioactive isotopes are recognized.
| द्रव्यमान संख्या | परमाणु द्रव्यमान (u) | प्राकृतिक प्रचुरता | अर्धायु | क्षय का प्रकार | |
|---|---|---|---|---|---|
| 139 स्थिर | 138.9063563 ± 0.0000024 | 99.9112% ± 0.0007% | स्थिर | stable |
विस्तृत गुण
सहसंयोजक त्रिज्याएँ (विस्तृत)
- सहसंयोजक त्रिज्या (प्यूक्को)
- 180 pm
- सहसंयोजक त्रिज्या (प्यूक्को, द्विबंध)
- 139 pm
- सहसंयोजक त्रिज्या (प्यूक्को, त्रिबंध)
- 139 pm
वान डर वाल्स त्रिज्याएँ
- Batsanov
- 250 pm
- Alvarez
- 298 pm
- UFF
- 352.2 pm
- MM3
- 278 pm
परमाणु और धात्विक त्रिज्याएँ
- परमाणु त्रिज्या (राह्म)
- 284 pm
- धात्विक त्रिज्या (C12)
- 187 pm
संख्यांकन मापक्रम
- Mendeleev
- 13
- Pettifor
- 33
- Glawe
- 32
विद्युतऋणात्मकता मापक्रम
- Ghosh
- 0
- Miedema
- 3
- Gunnarsson–Lundqvist
- 4
- Robles–Bartolotti
- 3
ध्रुवणीयता और परिक्षेपण
- द्विध्रुव ध्रुवणीयता
- 215 a.u.
- द्विध्रुव ध्रुवणीयता (अनिश्चितता)
- 20 a.u.
- C₆ (Gould–Bučko)
- 3730 Ha·Bohr6
रासायनिक बंधुता
- प्रोटॉन बंधुता
- 1013 kJ/mol
- गैसीय क्षारकता
- 991.9 kJ/mol
मीडेमा प्राचल
- मीडेमा मोलर आयतन
- 22.55 cm3/mol
- मीडेमा इलेक्ट्रॉन घनत्व
- 2
आपूर्ति जोखिम और अर्थशास्त्र
- उत्पादन संकेंद्रण
- 97
- सापेक्ष आपूर्ति जोखिम
- 10
- भंडार वितरण
- 50
- राजनीतिक स्थिरता (प्रमुख उत्पादक)
- 24
- राजनीतिक स्थिरता (सबसे अधिक भंडार वाला देश)
- 24
प्रावस्था संक्रमण और अपररूप
| गलनांक | 1193.15 K |
| क्वथनांक | 3737.15 K |
ऑक्सीकरण अवस्था की श्रेणियाँ
उन्नत संदर्भ डेटा
परिरक्षण स्थिरांक (13)
| n | कक्षक | σ |
|---|---|---|
| 1 | s | 1.1317 |
| 2 | p | 4.2044 |
| 2 | s | 15.0466 |
| 3 | d | 13.9398 |
| 3 | p | 18.8604 |
| 3 | s | 19.0569 |
| 4 | d | 32.2748 |
| 4 | f | 55.64 |
| 4 | p | 29.2936 |
| 4 | s | 28.2036 |
क्रिस्टल त्रिज्याओं का विवरण (6)
| आवेश | CN | प्रचक्रण | rcrystal (pm) | उत्पत्ति |
|---|---|---|---|---|
| 3 | VI | 117.2 | from r^3 vs V plots, | |
| 3 | VII | 124 | ||
| 3 | VIII | 130 | from r^3 vs V plots, | |
| 3 | IX | 135.6 | from r^3 vs V plots, | |
| 3 | X | 141 | ||
| 3 | XII | 150 | calculated, |
समस्थानिक क्षय के प्रकार (64)
| समस्थानिक | मोड | तीव्रता |
|---|---|---|
| 116 | B+ | — |
| 116 | B+p | — |
| 116 | p | — |
| 117 | p | 100% |
| 117 | B+ | — |
| 117 | B+p | — |
| 118 | B+ | — |
| 118 | B+p | — |
| 119 | B+ | — |
| 120 | B+ | 100% |
एक्स-रे प्रकीर्णन गुणक (711)
| ऊर्जा (eV) | f₁ | f₂ |
|---|---|---|
| 10 | — | 3.31251 |
| 10.1152 | — | 3.28769 |
| 10.2317 | — | 3.26306 |
| 10.3496 | — | 3.23861 |
| 10.4688 | — | 3.20975 |
| 10.5894 | — | 3.15961 |
| 10.7114 | — | 3.11024 |
| 10.8348 | — | 3.06165 |
| 10.9596 | — | 3.01382 |
| 11.0859 | — | 2.96673 |
अतिरिक्त डेटा
Estimated Crustal Abundance
The estimated element abundance in the earth's crust.
3.9×101 milligrams per kilogram
संदर्भ (1)
- [5] Lanthanum https://education.jlab.org/itselemental/ele057.html
Estimated Oceanic Abundance
The estimated element abundance in the earth's oceans.
3.4×10-6 milligrams per liter
संदर्भ (1)
- [5] Lanthanum https://education.jlab.org/itselemental/ele057.html
Sources
Sources of this element.
Lanthanum is found in rare-earth minerals such as cerite, monazite, allanite, and bastnasite. Monazite and bastnasite are principal ores in which lanthanum occurs in percentages up to 25 percent and 38 percent respectively. Misch metal, used in making lighter flints, contains about 25 percent lanthanum.
The availability of lanthanum and other rare earths has improved greatly in recent years. The metal can be produced by reducing the anhydrous fluoride with calcium.
संदर्भ (1)
- [6] Lanthanum https://periodic.lanl.gov/57.shtml
संदर्भ
(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 Lanthanum.
The element property data was retrieved from publications.