Protactinium metal. Its melting point is thought to be about 1,560°C (2,840°F) and its density about 15. The naturally occurring element protactinium is very costly and scarce. Niobium and tantalum are amphoteric metals as demonstrated by their ability to form both acid soluble complexes and alkaline soluble hexametalates, the simplest of these is the Lindqvist ion of the form M 6 O 198− (M = Nb Jun 21, 2012 · The mystery and witchcraft mostly came from protactinium's confusing chemical properties, not quite truly actinide yet not quite transition metal. Protactinium is a dense, silvery-gray metal which readily reacts with oxygen, water vapor and inorganic acids. Protactinium is a radioactive metal formed in the decay chain of uranium but not thorium (Fig. 9% protactinium, the world's only stock of the metal for many years tocome. Jun 28, 2025 · Protactinium (Pa) is a rare, radioactive metal with atomic number 91 and a silvery-gray appearance. It occurs in all uranium ores to the extent of 0. However, it tarnishes quickly when exposed to air. May 18, 2018 · Protactinium belongs in the actinides series in the periodic table. It is a dense, radioactive, silvery-gray actinide metal which readily reacts with oxygen, water vapor, and inorganic acids. Protactinium isotope 231 Pa (t 1/2 = 32,480 years) is the most important of all 24 known isotopes. The following reaction is one method for preparing protactinium metal under relatively extreme conditions: 2PaI5( s)→Δ 2 Pa( s)+5I2( s) Given 15. 03587 amu Melting Point: 1600. Protactinium metal primarily is generated from the decay of the rare isotope uranium 235 (via the very unstable thorium 231). It is a dense, silvery-gray metal which readily reacts with oxygen, water vapor and inorganic acids. They named the element brevium, which means brief. Herein, we report the synthesis of a Pa-peroxo cluster, A 6 Pa 4 O (O 2) 6 F 12 [A = Rb, Cs, (CH 3) 4 N], formed in pursuit of an actinide polyoxometalate. Another phase of this oxide with orthorhombic symmetry has chemical properties, health and environmental effects of protactinium Protactinium • Actinide Rare Earth Symbol: Pa Date of discovery: 1917 Name origin: Greek protos Appearance: unknown Discoverer: Fredrich Soddy Obtained from: fission of uranium, thorium, plutonium Melting point: 1873 K Boiling point: unknown Density [kg/m3]: 15370 Molar volume: 15. 1 pm, c = 323. This sample of uraninite contains some about 10 -6 grammes of actinium at any one time. Feb 12, 2018 · Here, the authors synthesize and study a tetranuclear protactinium peroxo cluster and demonstrate that protactinium represents an intersection of actinide (5f) and transition metal (6d) chemistries. Jul 6, 2024 · Explore the properties, uses, health risks, and fascinating facts about protactinium in Understanding Protactinium. This metal has around five isotopes with their mass numbers ranging between 212 to 238 and protactinium 231 is considered to be the most stable isotope with a half-life of about 32,760 years. Protactinium is a chemical element with the symbol (Pa) and atomic number 91. 9 pm). The element has atomic number 91 and element symbol Pa. Protactinium is the f-block element and it belongs to inner transition metals group. Almost all naturally occurring protactinium is the 231 isotope. When chemists understand their similarities in more detail, they may discover novel and yet-undiscovered applications for these and other related elements. Although it is part of the actinide series, its properties make it stand out in several ways: This was the longer-lived isotope protactinium-231, also coming from uranium, and its half-life is 32,500 years. The electron Explore detailed information on Protactinium (Pa) element - Atomic Number 91, atomic mass 231. Protactinium most often appears in compounds with a +5 oxidation state, giving it chemistry that straddles the Oct 19, 2023 · Protactinium normally exists in the oxidation state +5, while it may also take on +4, +3, or +2 states, as it forms a variety of chemical combinations. Apr 14, 2025 · Protactinium | Pa | CID 23945 - structure, chemical names, physical and chemical properties, classification, patents, literature, biological activities, safety Protactinium was discovered by Kasimir Fajans and Otto H. Valences of protactinium are: 2, 4,5. Discovery and naming Scientists first learned about radioactive elements toward the end of the nineteenth century. Mar 14, 2018 · The study, “ Protactinium and the intersection of actinide and transition metal chemistry,” appeared in the February 12 online issue of Nature Communications. Protactinium, uranium, neptunium, and plutonium all can be generated in the pentavalent oxidation state in aqueous media, although hydrolysis results in the formation of the dioxo species AnO2+ for all but protactinium. 276 x 10 4 years. 0359 Group # in Periodic Table: n/a Group Name: Actinides Period in Periodic Table: 7 Block of Periodic Table: f-block Discovered by: Kasimir Fajans, Oswald Helmuth Göhring (1913) Protactinium is a rare, radioactive element in the periodic table. Physical properties Protactinium is a bright shiny metal. Protactinium is a Actinide metal element, on the Periodic Table, with an atomic number of 91. Protactinium was first predicted by Dmitri Mendeleev in 1871. In 1959 and 1961,it was announced that the Great Britain Atomic Energy Authority extracted by a 12-stageprocess 125 g of 99. org is the world's leading website about minerals and where they come from. Protactinium is a rare metal - Protactinium, Element 91, is a rare and radioactive metal. It is a metal and a member of the actinide group of elements, which includes Protactinium is a dense, silvery-gray metal with atomic number 91. The protactinium metal is a radioactive, silvery, and shiny metal that slowly degrades in the presence of air to produce oxides. Aristid von Grosse produced 2 mg of Pa 2 O 5 in 1927, [10] and in 1934 performed the first isolation of elemental protactinium from 0. It is also found in spent fuel rods from nuclear reactors, from which it is extracted. Concentrations of protactinium in the This was the longer-lived isotope protactinium-231, also coming from uranium, and its half-life is 32,500 years. It is a Block F, Group 3, Period 7 element. 1 minutes) was first identified by Kasimir Fajans and O. This metal contains up to 5 isotopes with their mass numbers ranging between 212 to 238, and protactinium 231 can be considered to be the most stable isotope containing a half-life of about 32,760 years. 34 part per million of uranium. 0 °C (1873. Protactinium is a radioactive metal that is found in the actinide series of the periodic table. It is a dense, silvery-gray metal that belongs to the actinide series of elements. Protactinium (atomic number 91) is a metal discovered by Oswald Gohring and Kasimir Fajans in 1913. What is Protactinium Protactinium is a highly radioactive metal belonging to the family of actinides and denoted by the chemical symbol Pa [1]. Concentrations of protactinium in the Protactinium – Periodic Table – Atomic Properties Protactinium is a dense, silvery-gray metal which readily reacts with oxygen, water vapor and inorganic acids. Sellers , Sherman Fried , Robert E. It has 27 isotopes with mass numbers ranging from 212 to 238 out of which protactinium-231 is the most stable one with a half-life of 3. It belongs to the actinide series and occurs naturally in trace amounts in uranium ores as part of the uranium-235 decay chain. It emits alpha radiation and is produced through the decay of uranium-235. 25. Zachariasen Protactinium (Pa) Element Symbol: Pa Atomic Number: 91 Atomic Mass: 231. Apr 1, 2003 · This structural change is interpreted as reflecting an increase in $5f$-electron contribution to the bonding in protactinium over that initially present, becoming more similar to that present in alpha-uranium metal at atmospheric pressure. One method was the reduction of protactinium pentoxide using a stream of electrons in a The mystery and witchcraft mostly came from protactinium’s confusing chemical properties, not quite truly actinide yet not quite transition metal. Protactinium is a silver metallic element that is in the actinide group, with a bright metallic shine that it keeps for some time in the air. The isotope 233 Pa is of Aug 2, 2019 · Protactinium is a radioactive element predicted to exist in 1871 by Mendeleev, although it was not discovered until 1917 or isolated until 1934. Protactinium is, formally, the third element of the actinide series and the first having a 5f electron. [10] Its crystal structure is cubic, and the chemical composition is often non-stoichiometric, described as PaO 2. Protactinium ( Pa), a highly toxic metal, is one of the rarest and most expensive elements. Protactinium occurs naturally at concentrations of 0. Protactinium atoms join together in large numbers to form a giant metal molecule. Protactinium was first identified in 1913, and its name comes from the Greek "protos," meaning "first," as it is the precursor to uranium in the radioactive decay series. It belongs to the actinide series (period 7, f-block) of the periodic table and is extremely rare on Earth. Nov 21, 2020 · What is Protactinium Protactinium is a chemical element with atomic number 91 which means there are 91 protons and 91 electrons in the atomic structure. Mar 15, 2018 · Protactinium is an actinide element and sits between thorium and uranium on the periodic table. Göhring (DE) in 1913. Protactinium is a chemical element; it has symbol Pa and atomic number 91. Characteristics: Protactinium is a very rare shiny, silvery, highly radioactive metal that tarnishes slowly in air to the oxide. 0 °F) Boiling Point: Unknown Number of Protons/Electrons: 91 Number of Neutrons: 140 Classification: Rare Earth Crystal Structure: Orthorhombic Density @ 293 K: 15. In 1934, Aristid von Grosse reduced protactinium oxide to protactinium metal by decomposing its iodide (PaF 5) on a heated filament. Göhring first produced protactinium-234 in 1913 while examining the radioactive decay of uranium. It is superconductive at temperatures below 1. 1). Protactinium in the periodic table From Wikipedia, the free encyclopedia Protactinium is a chemical element with symbol Pa and atomic number 91. The periodic table is a chart that shows how chemical elements are related to one another. Trouvez les données physiques, configurations électroniques, propriétés chimiques, les états d'agrégation, isotopes (avec chaînes de désintégration) aussi bien que des informations historiques. Facts about Protactinium: Protactinium: Dense, silvery-grey, radioactive metal Fun fact about Protactinium: As the 5f and 6d orbitals switch filling Protactinium oxides are known for the metal oxidation states +2, +4 and +5. However, the metal is dangerous to handle because it and its compounds are both toxic and radioactive. With its atomic number 91, it exhibits intriguing chemical properties due to its position in the periodic table. Sep 1, 2024 · Protactinium in Periodic table Protactinium element is in period 7 and in actinides group of the Periodic table. Protactinium does not occur in Protactinium’s transition metal homologues are Nb and Ta, all three sharing a closed shell pentavalent oxidation state. Scroll down to see examples of Protactinium. Concentrations of protactinium in the Sep 17, 2013 · As a metal, protactinium is dense and silvery-gray with a bright metallic luster, which it retains for some time in air. Like most elements on the periodic table, protactinium is a silver-colored metal. Concentrations of protactinium in the This relates to the fact that the protactinium-231 decays by alpha decay to form actinium-227. Mindat. Its primary significance comes from its role in the decay chain of more common elements like uranium. 2 F). At most a few atoms at a time exist in a rock like this, and you can't see any of them. It forms various chemical compounds in which protactinium is usually present in the oxidation state +5, but it can Jan 1, 2018 · The element protactinium (Pa) is a short-lived nuclide belonging to the decay chain of 235-Uranium and the third element in the actinide series (Z = 91) with an atomic mass of 231. Sep 29, 2024 · Protactinium is a radioactive, silvery-gray metal with chemical properties similar to other actinides, such as uranium and thorium. It has 91 protons in its nucleus, which means it is the 91st element on the periodic table. Radioactive elements are elements that break apart all by themselves. Basic Information | Atomic Structure | Isotopes | Related Links | Citing This Page Basic Information Name: Protactinium Symbol: Pa Atomic Number: 91 Atomic Mass: 231. Notes on the properties of Protactinium: Atomic Mass: Atomic mass number given for longest lived isotope. At room temperature it is a tetragonal solid gray metal, with a calculated density of 15. Protactinium is a rare, poisonous and expensive element that is present in uranium ores in very small amounts. The anhydrous tetrafluoride complexes of thorium, protactinium, uranium, neptunium, and plutonium are known; all are halogen-bridged polymers in the solid state. Therefore Protactinium metal only exists in small amounts, most of it is found in nuclear waste. 035 88 u，属于 锕系元素，具有 放射性。鏷是银灰色、 密度 高的 金属，容易与 氧 、 水蒸汽 和无机 酸 反应。鏷在化合物中的 氧化態 主要是+5，但也存在+4和更加罕見的+3及+2氧化態。 鏷于 Jun 17, 2023 · Protactinium element (Pa) is in period 7 of a periodic table. Protactinium-231 was discovered by John Cranston and Frederick Soddy and Lisa Meitner and Otto Hahn in 1918. The half-life of the most stable isotope 231Pa is 32760 years. It is a silvery-grey, radioactive substance that is found in a few parts per trillion of Earth’s crust. Jan 1, 2016 · The element protactinium (Pa) is a short-lived nuclide belonging to the decay chain of 235-Uranium and the third element in the actinide series (Z = 91) with an atomic mass of 231. 0359. The pure metal was not isolated until 1934 by Alfred Grosse. H. When exposed to air, it combines easily with oxygen to form a whitish coating of protactinium German chemist Otto Hahn was involved in early work with protactinium. It is a very rare, silvery-white, extremely radioactive metal that resists alkalis, reacts with oxygen, acids and steam. It is chemically active, reacting with air, water and acids but not bases. 3-3 parts per million in uraninite ores, arising through uranium-235 decay with a half-life of 32,760 years. Protactinium is in the f-block and it is classified as an actinide on the periodic table. Jan 4, 2020 · Protactinium (Pa) is a shiny silver colored radioactive metal that has the atomic number 91 in the periodic table. Protactinium, also known as protoactinium, is an organic compound that is positioned left of uranium and right of thorium in the periodic table. The origin of the name comes from the Greek word protos meaning first. The most stable is white pentoxide Pa 2 O 5, which can be produced by igniting protactinium (V) hydroxide in air at a temperature of 500 °C. 37 g/cm 3 and an atomic radius of 1. Here are An isotope of protactinium (having mass number 234 and a half-life of 1. After which, it forms actinium -277 through alpha decay [3]. 18 × 10 -3 m 3 /mol Protons/Electrons: 91 Neutrons: 140 Shell structure: 2,8,18,32,20,9,2 Electron Nov 21, 2020 · What is Protactinium Protactinium is a chemical element with atomic number 91 which means there are 91 protons and 91 electrons in the atomic structure. The electron The silvery-white metal is extremely rare, very radioactive and highly poisonous. He predicted that an element exists between thorium and uranium. This metal and its derivatives are poisonous and radioactive, making them hazardous to handle. 6 pm) and β protactinium is cubic face-centered (a = 501. Protactinium is one of the rarest elements and is found in minute quantities in uranium minerals and ores, and can be extracted from these sources in gram quantities. 03588, physical & chemical properties, facts, uses, history, periodic table trends, isotopes, electron configuration, structure, abundance, and safety data. Elson , and W. Protactinium is a highly radioactive, hard, dense metal with a bright metallic luster when freshly prepared. The researchers used Argonne’s Laboratory Computing Resource Center and the work was funded by the DOE ’s Office of Science. Protactinium’s transition metal homologues are Nb and Ta, all three sharing a closed shell pentavalent oxidation state. Despite its position between thorium and uranium in the periodic table, protactinium finds no commercial applications due to its scarcity, high radioactivity (0. All its isotopes are radioactive, and the element is usually found only in trace amounts within uranium ores. He developed two methods for this. Protactinium metal is a dense, silvery-gray material with a bright metallic luster which it retains for some time in air but it does readily react with oxygen, water vapor and inorganic acids to form various compounds. Obtenez les faits pour l'élément Protactinium (Pa) [91] depuis le tableau périodique. The NpO 2+ ion is most stable in aqueous solutions; in contrast, UO 2+ and PuO 2+ disproportionate readily. An isotope of protactinium (having mass number 234 and a half-life of 1. 4 K. Originally called brevium by its discoverers because of the short life-time of the transition between Th-234 and U-234, a longer-lived isotope was eventually isolated and called protoactinium by Grosse. It retains a bright silvery luster for some time in the air. The number of electrons in each of Protactinium's shells is 2, 8, 18, 32, 20, 9, 2 and its electron configuration is [Rn] 5f 2 6d 1 7s 2. Download periodic table flashcards printable or compare Protactinium with other elements using SchoolMyKids interactive dynamic periodic table. Learn about its applications in various industries, its role in modern technology, and interesting trivia about this rare and radioactive element. It forms various chemical compounds, in which protactinium is usually present in the oxidation state +5, but it can also assume +4 and even +3 or +2 states. 15 K, 2912. It is a dense, radioactive, silvery-gray actinide metal which readily reacts with oxygen, water vapor and inorganic acids. Protactinium (Pa), radioactive chemical element of the actinoid series of the periodic table, rarer than radium; its atomic number is 91. Areas covered include atomic structure, physical properties, atomic interaction, thermodynamics, identification, atomic size, crystal structure, history, abundances, and nomenclature. In 1961, the Great Britain Atomic Energy Authority was able to produce 125 grams of 99. Gohring in 1913 as a short-lived member of the naturally occurring 238 U decay series and was given the name brevium , meaning brief. , 1979). It is found in pitchblende and ores form Zaire and is one of the rarest and most expensive naturally occurring elements. Its texture is smooth and lustrous, similar to other metallic elements. Niobium and tantalum are amphoteric metals as demonstrated by their Protactinium is an inner transition metal of the actinide series, situated in period seven of the periodic table, between thorium and uranium. Protactinium is a chemical element; it has symbol Pa and atomic number 91. 4 K (minus 457. Nov 14, 2025 · Protactinium is a rare radioactive actinide element exhibiting unique chemical and physical properties, fueling scientific research and specialized industrial applications globally. In 1949 the name was shortened from protoactinium to protactinium. Protactinium is one of the rarest elements on Earth. It exists in two crystalline forms: α-Protactinium is tetragonal body-centered (a = 393. For many years, the only supply of protactinium of any size was kept in Great Britain. The Preparation of Some Protactinium Compounds and the Metal1 Philip A. 4 g/cm 3 . Protactinium occurs in vanishingly small quantities in the natural decay chains of uranium and thorium minerals. Protactinium is a radioactive actinide group metal with the atomic symbol Pa, atomic number 91, and atomic weight 231. 048 Ci/g), and toxicity. It is superconductive below 1. oxide. 63 pm when XII-fold coordinated in its metallic state (Elson, 1954). 37 grams per cubic centimeter. Specific Heat: Value given for gas phase. Small amounts of protactinium are found naturally in uranium ores. Up to date, curated data provided by Mathematica 's ElementData function from Wolfram Research, Inc. Protactinium – Properties Jan 1, 1982 · As a consequence of the availability of macro-quantities of a nuclide with a reasonably long half-life, world-wide interest was generated in the chemistry of protactinium. Jan 21, 2025 · Protactinium (Pa) is a dense, silvery-gray metal belonging to the actinide series. Apr 30, 2025 · A rare and novel protactinium single crystal is synthesized, isolated, and characterized. The chemical symbol for Protactinium is Pa. This metal is found in uranium ores while its isotopes are present in uranium-238 and uranium-235. It was only in 1934 when the element was first isolated. Protactinium is a radioactive element, and its most stable isotope, protactinium-231, has a half-life of about 32,000 years. The superconducting properties of protactinium metal provide clear evidence that Pa is a true actinide element (Smith et al. The metal was Nov 26, 2021 · Protactinium is a dense, silvery-gray metal which readily reacts with oxygen, water vapor and inorganic acids. Protactinium: Photograph of protactinium-233 (darker circular area) taken at the National Reactor Testing Station in Idaho circa 1969. It is an Actinoid Metal with the symbol Pa. Kasimir Fajans and O. Protactinium is a highly toxic and radioactive rare earth metal that requires special handling. Protactinium is one of the rarest and most expensive naturally occurring elements. Protactinium metal is a shiny, radioactive and silvery metal that degrades slowly in the presence of air to form oxides. The complexes are isostructural; the metal center lies within a distorted square antiprismatic arrangement of fluoride ions. Protactinium has few uses, but becomes The protactinium metal was prepared by a Van Arkel process (Bohet and Müller, 1978) by thermal dissociation of protactinium iodide on a radiofrequency-heated tungsten sphere (Spirlet, 1979). Each entry has a full citation identifying its source. H. 63 pm when XII-fold coordinated in its metallic state (Elson 1954). Protactinium, Chemistry, Science, Chemistry Encyclopedia Protactinium (formerly protoactinium) is a chemical element; it has symbol Pa and atomic number 91. Much of this has been directed at the preparation of the metal and a wide range of compounds, and investigations of their chemical and physical properties. About Protactinium Molecular Structure Protactinium has the chemical symbol Pa. Mendeleev said there should be an element between thorium and uranium, but it evaded detection. Outside of science, no applications for protactinium metal exist. Feb 12, 2018 · The 5f and 6d atomic states cross in energy at protactinium (Pa), making it a potential intersection between transition metal and actinide chemistries. This confusion persisted until the actinide The name was shortened to Protactinium in 1949. The bright area is the light emanating from its radioactivity, which was used to photograph this rare image. 1 mg of Pa 2 O 5 using the iodide process: converting the oxide to an iodide and then reducing it in a vacuum with an electrically-heated metal filament: Occurrence, isolation & synthesis of protactinium © Michael Pilgaard Created: June 27, 2018 Legislation: Copyright, ownership information and cookies- and privacy We would like to show you a description here but the site won’t allow us. Mar 15, 2018 · Chemists have recently explored protactinium's multiple resemblances to more completely understand the relationship between the transition metals and the complex chemistry of the early Apr 1, 2003 · Protactinium occupies an important position in the actinide series of elements, as it represents the first of four elements (Pa-Pu) having 5f-electron character in their bonding at atmospheric 镤 pú （英語： protactinium；舊譯 鎃[6]），是一種 化學元素，其 化學符號 为 Pa， 原子序數 为91， 原子量 為 231. 9% pure protactinium, although they had to process about 55,000 kilograms of ore and spend about $500,000 to get it. Protactinium is highly radiotoxic, extremely toxic and must be handled with great care. Protactinium is a dense and silver-colored metal that is malleable and ductile. 8mg of reactant, how many milligrams of protactinium could be synthesized? =gPa (round to five decimal Feb 12, 2018 · The 5f and 6d atomic states cross in energy at protactinium (Pa), making it a potential intersection between transition metal and actinide chemistries. Description Named from the Greek word meaning “the first”, protactinium is a silvery, radioactive metal. Atomic Structure Protactinium as 91 protons and 140 neutrons in its nucleus giving it an Atomic Number of 91 and an atomic mass of 231 Our protactinium page has over 135 facts that span 55 different quantities. It is formed when uranium and other radioactive elements break down. It decays by alpha-emission. lrqay enarohoc nfsylfp mnsxvkqx rmti myczlv yrwz vmjquh xnju uant