Praseodymium (Pr)
lanthanideSolid
표준 원자량
140.90766 u전자 배치
[Xe] 6s2 4f3녹는점
930.85 °C끓는점
3519.85 °C밀도
6770 kg/m³산화 상태
0, +1, +2, +3, +4, +5전기 음성도(Pauling)
1.13제1 이온화 에너지
5.4702 eV발견 연도
1885원자 반지름
185 pm상세 정보
Praseodymium is a light lanthanide and one of the rare-earth elements. In nature it occurs with other lanthanides, chiefly in minerals such as monazite and bastnäsite, and only in the +3 oxidation state under normal geochemical conditions. Its chemistry is dominated by Pr³⁺ salts and oxides, but the element is more readily oxidized to Pr⁴⁺ than most neighboring lanthanides. Praseodymium is technologically important in permanent magnets, optical materials, ceramics, and specialized alloys.
Praseodymium is soft, silvery, malleable, and ductile. It is somewhat more resistant to corrosion in air than europium, lanthanum, cerium, or neodymium, but it does develop a green oxide coating that falls off when exposed to air. As with other rare-earth metals, it should be kept under a light mineral oil or sealed in plastic.
The name derives from the Greek prasios for "green" and didymos for "twin" because of the pale green salts it forms. Praseodymium was discovered by the Austrian chemist Carl Auer (Baron von Welsbach) in 1885, who separated it and the element neodymium from a didymium sample (didymium had previously been thought to be a separate element).
Praseodymium was discovered by Carl F. Auer von Welsbach, an Austrian chemist, in 1885. He separated praseodymium, as well as the element neodymium, from a material known as didymium. Today, praseodymium is primarily obtained through an ion exchange process from monazite sand ((Ce, La, Th, Nd, Y)PO4), a material rich in rare earth elements.
From the Greek word prasios, green, and didymos, twin. In 1841 Mosander extracted the rare earth didymia from lanthana; in 1879, Lecoq de Boisbaudran isolated a new earth, samaria, from didymia obtained from the mineral samarskite. Six years later, in 1885, von Welsbach separated didymia into two others, praseodymia and neodymia, which gave salts of different colors. As with other rare earths, compounds of these elements in solution have distinctive sharp spectral absorption bands or lines, some of which are only a few Angstroms wide.
Pure praseodymium is a soft, silvery metal with a pale yellow cast when freshly cut. It tarnishes readily in air, forming oxide layers that can spall, so metal is usually stored under mineral oil, inert gas, or vacuum. It is malleable and reacts slowly with water, faster with dilute acids.
The largest use of praseodymium is in neodymium-iron-boron magnet alloys, where it can partly replace neodymium and help adjust magnetic and processing properties. Praseodymium compounds color glasses and ceramic glazes yellow to green, and mixed praseodymium-neodymium glass is used in didymium filters for glassworking eye protection. Praseodymium is also used in some mischmetal alloys, polishing and catalytic materials, and doped optical crystals or fibers for specialized lasers and signal devices.
Praseodymium's primary use is as an alloying agent with magnesium to create high-strength metals that are used in aircraft engines. Praseodymium also makes up about 5% of Misch metal, a material that is used to make flints for lighters. Praseodymium forms the core of carbon arc lights which are used in the motion picture industry for studio lighting and projector lights. Praseodymium is added to fiber optic cables as a doping agent where it is used as a signal amplifier. Praseodymium salts are used to give glasses and enamels a yellow color. Praseodymium is also a component of didymium glass, which is used to make certain types of welder's and glass blower's goggles.
Misch metal, used in making cigarette lighters, contains about 5% praseodymium metal. The rare-earth oxides, including Pr2O3 are among the most refractory substances known. Along with other rare earths, it is widely used as a core material for carbon arcs used by the motion picture industry for studio lighting and projection. Salts of praseodymium are used to color glasses and enamels; when mixed with certain other materials, praseodymium produces an intense and unusually clean yellow color in glass. Didymium glass, of which praseodymium is a component, is a colorant for welders goggles.
Isotopes in Medicine
Because of its relatively short half-life (19.12 h) and decay primarily by beta decay (96.3 percent beta decay and 3.7 percent alpha decay), 142Pr has been proposed for two main innovative applications in medicine, namely in microsphere brachytherapy and in eye plaque brachytherapy [425] M. C. Ferreira. Dosimetric Study of Beta-Minus Emitter Praseodymium-142: Applications in Microsphere Brachytherapy for Hepatocellular Carcinoma and Brachytherapy for Ocular Squamous Cell Carcinoma, East Carolina University Greenville, North Carolina, USA (2013).. 142Pr is advantageous because penetration of the beta fraction of the radiation is limited to a few millimeters in tissue, therefore limiting the dose of radiation to the treated site. 142Pr may be produced either by fast neutron activation or thermal neutron activation of stable 141Pr.
Research in metal-bearing radiopharmaceuticals is being conducted to determine the most efficient way to produce and process radioactive metals for in vivo tracing. This research has led to the development of a potential radionuclide generator that administers radioactive metal complexes to be observed during positron emission tomography (PET) imaging. A n(140Nd)/n(140Pr) amount-ratio radionuclide generator has been designed to administer 140Pr complexes, such as 140Pr-DTPA, to be used as a tracer during a PET scan [426] K. P. Zhernosekov. Radiochemical Aspects of Production and Processing of Radiometals for Preparation of Metalloradiopharmaceuticals, Johannes Gutenberg-Universität Mainz: Department of Chemistry, Pharmacy and Earth Sciences (2017), Feb. 27; https://publications.ub.uni-mainz.de/theses/volltexte/2006/1043/pdf/1043.pdf.. The half-life of 140Pr is 3.4 min. The n(140Nd)/n(140Pr) ratio radionuclide generators can also be used for administering 140Pr-phosphonate complexes to identify the development of skeletal metastases. Once the skeletal metastases are found, 153Sm-EDTMP can be administered as a radiotherapeutic agent to treat bone cancer (Fig. IUPAC.59.1) [426] K. P. Zhernosekov. Radiochemical Aspects of Production and Processing of Radiometals for Preparation of Metalloradiopharmaceuticals, Johannes Gutenberg-Universität Mainz: Department of Chemistry, Pharmacy and Earth Sciences (2017), Feb. 27; https://publications.ub.uni-mainz.de/theses/volltexte/2006/1043/pdf/1043.pdf.. The half-life of 153Sm is 1.9 days.
Praseodymium forms mainly trivalent compounds containing Pr³⁺, including praseodymium(III) chloride, PrCl₃, praseodymium(III) fluoride, PrF₃, and praseodymium(III) oxide, Pr₂O₃. Mixed-valence and tetravalent oxide chemistry is important: praseodymium(IV) oxide, PrO₂, and the nonstoichiometric oxide often written Pr₆O₁₁ are useful oxidizing and ceramic materials. Praseodymium salts are commonly green, and their optical absorption bands are sharp because 4f electrons are partly shielded from the ligand environment.
See more information at the Praseodymium compound page.
Praseodymium metal dust and filings can burn, and freshly divided material should be treated as a fire risk. Soluble praseodymium salts have low to moderate acute toxicity compared with many heavy metals, but they are not nutrients and should not be inhaled or ingested. Industrial hazards mainly involve dust exposure, reactive metal handling, hot processing, and co-exposure to acids, fluorides, or other chemicals used in separation and alloy production.
Praseodymium is dispersed in the crust with other light rare-earth elements and is concentrated by geological processes in phosphate and carbonate minerals. It is generally immobile in neutral soils and waters because Pr³⁺ strongly adsorbs to clays, oxides, and organic matter or precipitates with phosphate and carbonate. Mining and processing can release rare-earth-bearing dusts and tailings, but praseodymium is not known to have a specific biological role.
Praseodymium is produced as part of rare-earth mining and separation rather than from ores mined solely for Pr. Bastnäsite, monazite, and related concentrates are chemically cracked, and solvent extraction or ion-exchange methods separate the closely similar lanthanides. Demand is strongly linked to high-performance permanent magnets, where praseodymium and neodymium are often managed together as a didymium-rich stream. Supply is constrained by rare-earth separation capacity, environmental controls, and the need to balance production of many co-occurring lanthanides. Recycling from magnets and manufacturing scrap is technically possible and increasingly important, but separation from complex products remains difficult.
The element occurs along with other rare-earth elements in a variety of minerals. Monazite and bastnasite are the two principal commercial sources of the rare-earth metals. It was prepared in relatively pure form in 1931.
Praseodymium is much less abundant in the cosmos than iron-group elements but is a normal product of neutron-capture nucleosynthesis. Its stable isotope, ¹⁴¹Pr, is formed through s-process and r-process pathways in evolved stars and explosive events. In planetary materials it follows other refractory lithophile rare-earth elements and is enriched in differentiated crustal rocks relative to primitive mantle materials.
- Natural praseodymium is essentially monoisotopic, consisting of stable ¹⁴¹Pr.
- The name comes from Greek words meaning “green twin,” referring to the color of its salts and its separation from didymr
- Pr₆O₁₁ is often called praseodymium oxide, although it is not a simple single-valence oxide.
- Praseodymium can replace part of neodymium in many commercial magnet compositions.
- Pr³⁺ absorption lines can give praseodymium glass a distinctive yellow-green filter behavior.
이미지
특성
물리적 특성
- 원자 반지름(경험값)
- 185 pm 모든 원소의 원자 반지름(경험값) 비교 →
- 공유 결합 반지름
- 203 pm 모든 원소의 공유 결합 반지름 비교 →
- 반데르발스 반지름
- 239 pm 모든 원소의 반데르발스 반지름 비교 →
- 밀도
- 6770 kg/m³ 모든 원소의 밀도 비교 →
- 몰 부피
- 0.0208 L/mol
- STP에서의 상
- 고체 모든 원소의 STP에서의 상 비교 →
- 녹는점
- 930.85 °C 모든 원소의 녹는점 비교 →
- 끓는점
- 3519.85 °C 모든 원소의 끓는점 비교 →
- 열전도율
- 12.5 W/(m·K) 모든 원소의 열전도율 비교 →
- 비열
- 0.193 J/(g·K) 모든 원소의 비열 비교 →
- 몰 열용량
- 27.2 J/(mol·K) 모든 원소의 몰 열용량 비교 →
- 결정 구조
- 육방 조밀 충전 모든 원소의 결정 구조 비교 →
화학적 특성
- 전기 음성도(Pauling)
- 1.13 모든 원소의 전기 음성도(Pauling) 비교 →
- 전자 친화도
- 0.962 eV
- 제1 이온화 에너지
- 5.4702 eV 모든 원소의 제1 이온화 에너지 비교 →
- 제2 이온화 에너지
- 10.631037 eV 모든 원소의 제2 이온화 에너지 비교 →
- 제3 이온화 에너지
- 21.623774 eV 모든 원소의 제3 이온화 에너지 비교 →
- 제4 이온화 에너지
- 38.981134 eV 모든 원소의 제4 이온화 에너지 비교 →
- 제5 이온화 에너지
- 57.530198 eV 모든 원소의 제5 이온화 에너지 비교 →
- 산화 상태
- 0, +1, +2, +3, +4, +5 모든 원소의 산화 상태 비교 →
- 원자가 전자
- 3 모든 원소의 원자가 전자 비교 →
- 전자 배치
- [Xe] 6s2 4f3
열역학적 특성
- 융해열
- 0.07141006 eV 모든 원소의 융해열 비교 →
- 기화열
- 3.078199 eV 모든 원소의 기화열 비교 →
- 승화열
- 3.430585 eV
- 원자화열
- 3.430585 eV
- 원자화 엔탈피
- 3.699021 eV
핵 특성
- 양성자 수
- 59 모든 원소의 양성자 수 비교 →
- 중성자 수
- 82 모든 원소의 중성자 수 비교 →
- 알려진 동위원소 수
- 41 모든 원소의 알려진 동위원소 수 비교 →
- 안정 동위원소 수
- 1 모든 원소의 안정 동위원소 수 비교 →
- 가장 안정한 동위원소
- Pr-141
- 발견 연도
- 1885
존재비
- 존재비(지각)
- 9.2 mg/kg 모든 원소의 존재비(지각) 비교 →
- 존재비(해양)
- 6.4 × 10−7 mg/L 모든 원소의 존재비(해양) 비교 →
결정 구조
- 격자 상수 a
- 367 pm
전자 구조
- 전자껍질별 전자 수
- 2, 8, 18, 21, 8, 2 모든 원소의 전자껍질별 전자 수 비교 →
식별자
- CAS 등록 번호
- 7440-10-0 모든 원소의 CAS 등록 번호 비교 →
- 항 기호
- 4I°9/2
- InChI
- InChI=1S/Pr
- InChI 키
- PUDIUYLPXJFUGB-UHFFFAOYSA-N
전자 배치 측정값
Pr: 4f³ 6s²[Xe] 4f³ 6s²1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 5s² 5p⁶ 4f³ 6s²원자 모형
동위원소에 따라 중성자 수, 질량, 안정성은 달라지지만, 중성 원자의 전자 배치는 달라지지 않습니다.
개략적인 원자 모형이며 실제 비율과 다릅니다.
원자 지문
방출 / 흡수 스펙트럼
동위원소 분포
| 질량수 | 원자 질량(u) | 천연 존재비 | 반감기 |
|---|---|---|---|
| 141 안정 | 140.9076576 ± 0.0000023 | 100.0000% | 안정 |
상 / 상태
이유: 녹는점(930.85 °C)보다 905.9 °C 낮음
개략도이며 실제 비율과 다름
상전이점
전이 에너지
녹는점에서 1 mol을 녹이는 데 필요한 에너지
끓는점에서 1 mol을 기화시키는 데 필요한 에너지
승화점에서 1 mol을 승화시키는 데 필요한 에너지
밀도
표준 조건에서
표준 조건에서
원자 스펙트럼
전체 59개 중 10개를 표시합니다. 이온 전하순으로 정렬되었습니다(오름차순).
보유 스펙트럼선 데이터 ?
| 이온 | 전하 | 총 스펙트럼선 수 | 전이 확률 | 준위 표기 |
|---|---|---|---|---|
| Pr I | 0 | 182 | 0 | 0 |
| Pr II | +1 | 548 | 172 | 356 |
| Pr III | +2 | 372 | 0 | 0 |
| Pr IV | +3 | 135 | 0 | 0 |
| Pr V | +4 | 12 | 0 | 0 |
보유 에너지 준위 데이터 ?
| 이온 | 전하 | 준위 |
|---|---|---|
| Pr I | 0 | 430 |
| Pr II | +1 | 201 |
| Pr III | +2 | 430 |
| Pr IV | +3 | 104 |
| Pr V | +4 | 9 |
| Pr VI | +5 | 2 |
| Pr VII | +6 | 2 |
| Pr VIII | +7 | 2 |
| Pr IX | +8 | 2 |
| Pr X | +9 | 2 |
이온 반지름
| 전하 | 배위 | 스핀 | 반지름 |
|---|---|---|---|
| +3 | 6 | 해당 없음 | 99 pm |
| +3 | 8 | 해당 없음 | 112.6 pm |
| +3 | 9 | 해당 없음 | 117.9 pm |
| +4 | 6 | 해당 없음 | 85 pm |
| +4 | 8 | 해당 없음 | 96 pm |
화합물
동위원소 (1)
| 질량수 | 원자 질량(u) | 천연 존재비 | 반감기 | 붕괴 방식 | |
|---|---|---|---|---|---|
| 141 안정 | 140.9076576 ± 0.0000023 | 100.0000% | 안정 | stable |
확장 특성
공유 결합 반지름(확장)
- 공유 결합 반지름(Pyykkö)
- 176 pm
- 공유 결합 반지름(Pyykkö, 이중 결합)
- 138 pm
- 공유 결합 반지름(Pyykkö, 삼중 결합)
- 128 pm
반데르발스 반지름
- Alvarez
- 292 pm
- UFF
- 360.6 pm
- MM3
- 273 pm
원자 및 금속 반지름
- 원자 반지름(Rahm)
- 286 pm
번호 척도
- Mendeleev
- 17
- Pettifor
- 31
- Glawe
- 30
전기 음성도 척도
- Ghosh
- 0
- Miedema
- 3
- Gunnarsson–Lundqvist
- 4
- Robles–Bartolotti
- 4
분극률 및 분산
- 쌍극자 분극률
- 216 a.u.
- 쌍극자 분극률(불확도)
- 20 a.u.
- C₆ (Gould–Bučko)
- 3760 Ha·Bohr6
미데마 매개변수
- 미데마 몰 부피
- 20.79 cm3/mol
- 미데마 전자 밀도
- 2
공급 위험 및 경제성
- 생산 집중도
- 97
- 상대적 공급 위험
- 10
- 매장량 분포
- 50
- 정치적 안정성(최대 생산국)
- 24
- 정치적 안정성(최대 매장국)
- 24
상전이 및 동소체
| 녹는점 | 1204.15 K |
| 끓는점 | 3793.15 K |
산화 상태 분류
심화 참고 데이터
차폐 상수 (13)
| n | 오비탈 | σ |
|---|---|---|
| 1 | s | 1.1694 |
| 2 | p | 4.2306 |
| 2 | s | 15.538 |
| 3 | d | 13.8476 |
| 3 | p | 19.1756 |
| 3 | s | 19.499 |
| 4 | d | 32.7028 |
| 4 | f | 37.8992 |
| 4 | p | 29.9432 |
| 4 | s | 28.6668 |
결정 반지름 상세 정보 (5)
| 전하 | CN | 스핀 | rcrystal (pm) | 기원 |
|---|---|---|---|---|
| 3 | VI | 113 | from r^3 vs V plots, | |
| 3 | VIII | 126.6 | from r^3 vs V plots, | |
| 3 | IX | 131.9 | from r^3 vs V plots, | |
| 4 | VI | 99 | from r^3 vs V plots, | |
| 4 | VIII | 110 | from r^3 vs V plots, |
동위원소 붕괴 방식 (58)
| 동위원소 | 모드 | 세기 |
|---|---|---|
| 121 | p | 100% |
| 122 | B+ | — |
| 122 | B+p | — |
| 123 | B+ | — |
| 123 | B+p | — |
| 124 | B+ | 100% |
| 124 | B+p | — |
| 125 | B+ | 100% |
| 125 | B+p | — |
| 126 | B+ | 100% |
X선 산란 인자 (508)
| 에너지 (eV) | f₁ | f₂ |
|---|---|---|
| 10 | — | 1.26325 |
| 10.1617 | — | 1.25455 |
| 10.3261 | — | 1.24591 |
| 10.4931 | — | 1.23732 |
| 10.6628 | — | 1.22879 |
| 10.8353 | — | 1.22033 |
| 11.0106 | — | 1.21192 |
| 11.1886 | — | 1.20357 |
| 11.3696 | — | 1.19528 |
| 11.5535 | — | 1.18704 |
추가 데이터
Estimated Crustal Abundance
The estimated element abundance in the earth's crust.
9.2 milligrams per kilogram
참고 문헌 (1)
- [5] Praseodymium https://education.jlab.org/itselemental/ele059.html
Estimated Oceanic Abundance
The estimated element abundance in the earth's oceans.
6.4×10-7 milligrams per liter
참고 문헌 (1)
- [5] Praseodymium https://education.jlab.org/itselemental/ele059.html
Sources
Sources of this element.
The element occurs along with other rare-earth elements in a variety of minerals. Monazite and bastnasite are the two principal commercial sources of the rare-earth metals. It was prepared in relatively pure form in 1931.
참고 문헌 (1)
- [6] Praseodymium https://periodic.lanl.gov/59.shtml
Production
Production of this element (from raw materials or other compounds containing the element).
Ion-exchange and solvent extraction techniques have led to much easier isolation of the rare earths and the cost has dropped greatly in the past few years. Praseodymium can be prepared by several methods, such as by calcium reduction of the anhydrous chloride of fluoride.
참고 문헌 (1)
- [6] Praseodymium https://periodic.lanl.gov/59.shtml
참고 문헌
(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 Praseodymium.
The element property data was retrieved from publications.