Neptunium - Wikiparency

# Neptunium ## 🧊 Neptunium · 3D (three.js) <iframe src="https://wikitube-elements.netlify.app/?el=Np&embed=1" width="100%" height="620" frameborder="0" style="border:0;border-radius:12px;overflow:hidden" allowfullscreen loading="lazy" title="The Elements 3D microsim - Neptunium"></iframe> *Neptunium in the live three.js Elements explorer — drag to orbit the atom, click any tile to compare, slide the temperature.* · [▶ open full](https://wikitube-elements.netlify.app/?el=Np)  !Neptunium plate.svg *Plate 93 of 118 - animated Bohr shells, stylized per Madelung filling; engraving style per house Arcanity kit.* ## Microsim To Do *Claimable rows, house pattern. Real Wikipedia articles only.* - Transuranium element - neptunium as first of the beyond-uranium metals - Nuclear transmutation - creating neptunium from uranium via neutron capture - Neutron capture - the mechanism for neptunium synthesis in reactors - [[Radioactive_decay|Radioactive decay]] - neptunium-237 and the actinide series ## Links (Wikipedia order)  `Acetate` · `Acid` · `Actinide` · [[Actinium]] · `Alkali_metal` · `Alkaline_earth_metal` · [[Alpha_decay]] · [[Alpha_particle]] · [[Aluminium]] · `Aluminium_bromide` · [[Americium]] · `Americium-241` · `Amine` · `Ammonia` · `Ampoule` · `Antimonide` · [[Antimony]] · [[Argon]] · `Aristid_von_Grosse` · [[Arsenic]] · `Arsenide` · `Arthur_Wahl` · [[Astatine]] · `Atomic_number` · `Atomic_radius` · `Aufbau_principle` · `Azide` · [[Barium]] · `Barium_sulfate` · `Base_(chemistry)` · `Belgian_Congo` · `Bentonite` · `Benzene` · [[Berkelium]] · [[Beryllium]] · `Beta-decay_stable_isobars` · [[Beta_decay]] · `Bicarbonate` · `Biotechnology` · [[Bismuth]] · `Block_(periodic_table)` · [[Bohrium]] · [[Boiling_point]] · `Bone` · [[Boron]] · `Boron_group` · `Boron_phosphate` · `Bremsstrahlung` · `Bromide` · [[Bromine]] · `Bromine_pentafluoride` · `Bromine_trifluoride` · `Butanol` · `CAS_Registry_Number` · [[Cadmium]] · [[Caesium]] · [[Calcium]] · [[Californium]] · `Carbide` · [[Carbon]] · `Carbon_dioxide` · `Carbon_disulfide` · `Carbon_group` · `Carbon_tetrachloride` · `Carbonate` · `Celsius` · [[Cerium]] · `Chalcogen` · `Chelation` · [[Chemical_element]] · `Chemical_formula` · `Chemical_symbol` · `Chemical_transport_reaction` · `Chloride` · [[Chlorine]] · `Chromatography` · [[Chromium]] · `Clay` · [[Cobalt]] · `Colloid` · `Concrete` · `Congener_(chemistry)` · `Coordination_complex` · [[Copernicium]] · [[Copper]] · `Coprecipitation` · `Cosmic_ray_spallation` · `Covalent_bond` · `Covalent_radius` · `Critical_mass` · `Cross_section_(physics)` · [[Crystal_structure]] · [[Curium]] · `Cyclopentadienyl` · `Cyclotron` · [[Darmstadtium]] · [[Decay_chain]] · [[Decay_product]] · `Deep_geological_repository` · [[Density]] · `Denticity` · `Diatomic_molecule` · `Disproportionation` · `Dmitri_Mendeleev` · `Doctor_of_Science` · [[Dubnium]] · `Ductility` · [[Dysprosium]] · `Edwin_McMillan` · [[Einsteinium]] · `Electric_arc_furnace` · `Electrical_resistivity_and_conductivity` · `Electron_capture` · `Electron_configuration` · `Electron_shell` · `Electronegativity` · `Electronvolt` · `Electroplating` · `Emilio_Segrè` · `Enriched_uranium` · `Enrico_Fermi` · `Enthalpy_of_fusion` · `Enthalpy_of_vaporization` · `Equilibrium_constant` · [[Erbium]] · `Ethanol` · [[Europium]] · `Extraction_(chemistry)` · `Fast-neutron_reactor` · [[Fermium]] · [[Flerovium]] · `Flowchart` · `Fluoride` · [[Fluorine]] · [[Francium]] · `Fritz_Strassmann` · `Frédéric_Joliot-Curie` · [[Gadolinium]] · [[Gallium]] · `Gamma_ray` · [[Germanium]] · `Glenn_T._Seaborg` · `Goethite` · [[Gold]] · `Granodiorite` · `Graphite` · `Group_(periodic_table)` · `Group_10_element` · `Group_11_element` · `Group_12_element` · `Group_3_element` · `Group_4_element` · `Group_5_element` · `Group_6_element` · `Group_7_element` · `Group_8_element` · `Group_9_element` · [[Hafnium]] · [[Half-life]] · `Halide` · `Halogen` · [[Hassium]] · [[Helium]] · `Hematite` · [[Holmium]] · `Horia_Hulubei` · `Hydride` · [[Hydrogen]] · `Hydrogen_fluoride` · `Hydrogen_sulfide` · `Hydrolysis` · `Ida_Noddack` · [[Indium]] · `Induced_radioactivity` · `Iodate` · `Iodide` · [[Iodine]] · `Ion_exchange` · [[Ionization_energy]] · `Ionizing_radiation` · [[Iridium]] · [[Iron]] · `Irène_Joliot-Curie` · `Isomorphism_(crystallography)` · `Isostructural` · `Isotope` · `Isotopes_of_aluminium` · `Isotopes_of_lead` · `Isotopes_of_neptunium` · `Isotopes_of_phosphorus` · `Isotopes_of_plutonium` · `Isotopes_of_protactinium` · `Kaolinite` · `Kelvin` · [[Krypton]] · `Lactic_acid` · `Lanthanide` · `Lanthanide_contraction` · [[Lanthanum]] · `Lattice_constant` · [[Lawrencium]] · [[Lead]] · `Ligand` · `Lise_Meitner` · `List_of_chemical_element_name_etymologies` · `List_of_data_references_for_chemical_elements` · [[Lithium]] · `Lithium_bromide` · `Lithium_chloride` · [[Livermorium]] · `Los_Alamos_National_Laboratory` · [[Lutetium]] · [[Magnesium]] · `Magnetism` · `Magnetite` · [[Manganese]] · `Manhattan_Project` · `Mass_number` · `Matrix_(chemical_analysis)` · [[Meitnerium]] · `Melting_point` · [[Mendelevium]] · [[Mercury_(element)]] · `Metal` · `Metalloid` · `Microgram` · `Minor_actinide` · `Molar_concentration` · `Molar_heat_capacity` · [[Molybdenum]] · [[Moscovium]] · `Natural_abundance` · `Nauka_(publisher)` · [[Neodymium]] · [[Neon]] · `Neptune` · `Neptune_(mythology)` · `Neptunium(III)_bromide` · `Neptunium(III)_chloride` · `Neptunium(III)_fluoride` · `Neptunium(III)_iodide` · `Neptunium(IV)_fluoride` · `Neptunium(IV)_oxide` · `Neptunium(V)_fluoride` · `Neptunium(V)_oxide` · `Neptunium(VI)_fluoride` · `Neptunium_arsenide` · `Neptunium_diarsenide` · `Neptunium_nitride` · `Neptunium_sulfides` · `Neptunium_tetrabromide` · `Neptunium_tetrachloride` · `Neptunium_trioxide` · `Neptunyl_carbonates` · `Neptunyl_fluoride` · [[Neutron]] · `Neutron_capture` · `Nevada` · [[Nickel]] · `Niels_Bohr` · [[Nihonium]] · [[Niobium]] · `Nitrate` · `Nitric_acid` · `Nitride` · [[Nitrogen]] · `Nobel_Prize_in_Physics` · [[Nobelium]] · [[Noble_gas]] · `Non-stoichiometric_compound` · `Norman_Greenwood` · `Nuclear_fission` · `Nuclear_fuel_cycle` · `Nuclear_power` · `Nuclear_reactor` · `Nuclear_transmutation` · `Nuclear_weapon` · [[Oganesson]] · `Orthorhombic_crystal_system` · [[Osmium]] · `Otto_Hahn` · `Oxalate` · `Oxidation_state` · `Oxidizing_agent` · `Oxohalide` · [[Oxygen]] · `Ozone` · `PH` · `Pacific_War` · [[Palladium]] · `Partial_Nuclear_Test_Ban_Treaty` · `Pascal_(unit)` · `Pearson_symbol` · `Perchlorate` · `Perchloric_acid` · `Period_(periodic_table)` · `Period_1_element` · `Period_2_element` · `Period_3_element` · `Period_4_element` · `Period_5_element` · `Period_6_element` · `Period_7_element` · `Periodic_table` · `Peroxide` · `Phase_(matter)` · [[Phase_transition]] · `Phosphate` · `Phosphide` · `Phosphine` · [[Phosphorus]] · `Physical_Review` · `Picometre` · [[Platinum]] · [[Plutonium]] · `Plutonium-238` · `Plutonium-239` · `Plutonium-244` · `Plutonium_hexafluoride` · `Plutonium_nitride` · `Pnictogen` · [[Polonium]] · [[Potassium]] · [[Praseodymium]] · `Precipitation_(chemistry)` · `Precursor_(chemistry)` · `Primordial_nuclide` · [[Promethium]] · [[Protactinium]] · [[Proton]] · `Pyrimidine` · `Pyrophoricity` · `Quartz` · [[Radioactive_decay]] · `Radioactive_tracer` · [[Radium]] · [[Radon]] · `Red_phosphorus` · `Redox` · `Reducing_agent` · [[Rhenium]] · [[Rhodium]] · [[Roentgenium]] · `Room_temperature` · [[Rubidium]] · [[Ruthenium]] · [[Rutherfordium]] · [[Samarium]] · [[Scandium]] · [[Seaborgium]] · `Selenide` · [[Selenium]] · `Semimetal` · [[Silicon]] · [[Silver]] · `Smoke_detector` · [[Sodium]] · `Sodium_perchlorate` · `Soil` · `Solar_System` · `Solid` · `Sorption` · `Space_group` · `Spacecraft` · `Spectral_line` · `Spectroscopy` · `Spent_nuclear_fuel` · [[Spontaneous_fission]] · `Standard_temperature_and_pressure` · [[Strontium]] · `Sublimation_(phase_transition)` · `Sulfate` · `Sulfide` · [[Sulfur]] · [[Superconductivity]] · `Synthetic_radioisotope` · [[Tantalum]] · `Tarnish` · [[Technetium]] · `Telluride_(chemistry)` · [[Tellurium]] · [[Tennessine]] · [[Terbium]] · `Tetrahydrofuran` · [[Thallium]] · `Thiocyanate` · [[Thorium]] · [[Thulium]] · `Timeline_of_chemical_element_discoveries` · [[Tin]] · [[Titanium]] · `Toluene` · `Trace_radioisotope` · `Transition_metal` · `Tributyl_phosphate` · `Triple_point` · `Tuff` · [[Tungsten]] · `University_of_California,_Berkeley` · [[Uranium]] · `Uranium-233` · `Uranium-235` · `Uranium-236` · `Uranium-238` · `Uranium_hexafluoride` · `Uranium_ore` · `Uranocene` · `Uranus` · `Uranyl` · `Valence_electron` · [[Vanadium]] · `Vapor_pressure` · `Walter_Greiner` · [[Wayback_Machine]] · `Weak_interaction` · [[Xenon]] · [[Ytterbium]] · [[Yttrium]] · `Yvette_Cauchois` · [[Zinc]] · [[Zirconium]] > **Official MAIN - Chemical element, Z = 93.** Part of the Elements Canon (one canonical page per element). Infobox grounded in [Wikipedia: List of chemical elements](https://en.wikipedia.org/wiki/List_of_chemical_elements), fetched 2026-07-08. Full article: [Wikipedia: Neptunium](https://en.wikipedia.org/wiki/Neptunium).  ## Key facts (infobox) | | | |---|---| | Symbol - Z | Np - 93 | | Group - Period - Block | f - 7 - f-block | | Atomic weight (Da) | [237] | | Density (g/cm3) | 20.45 | | Melting - Boiling (K) | 917 - 4273 | | Electronegativity (Pauling) | 1.36 | | Crustal abundance (mg/kg) | <=3e-12 | | Origin | from decay | | Phase (STP) | solid | | Name origin | Neptune, the eighth planet | *Bracketed weights are the mass number of the most stable isotope; values in parentheses are predictions (per the source table).* ## Story Neptunium was synthesized in 1940 by Edwin McMillan and Philip Abelson at the University of California Berkeley by bombarding uranium-238 with neutrons. Following the convention of naming transuranium elements after planets beyond uranium (Uranus → uranium), they named the element after Neptune, the eighth planet. Neptunium-237, the longest-lived isotope, has a half-life of 2.14 million years. [model-prior - verify] Neptunium was the first synthetic transuranium element ever created, opening the door to the discovery of all the heavy elements that followed. Neptunium is a silvery-gray actinide metal and is highly radioactive and toxic. It does not occur naturally on Earth (its radioactive decay is too short-lived), but trace amounts are produced in nuclear reactors as a byproduct of uranium fission. Neptunium has no practical applications; it is of interest mainly to nuclear physicists and chemists studying transuranium chemistry. Most neptunium in existence is produced in controlled laboratory settings. In the canon, neptunium represents the moment when human chemistry crossed the threshold of the periodic table—it is the first element heavier than uranium, created by human hands, and it signals the beginning of the realm of purely synthetic elements. ## Corpus connections Neptunium marks the threshold where human chemistry enters the transuranium realm. It was the first element heavier than uranium, synthesized in 1940 and opening the door to modern transuranium discovery. - R.E.A.C.T.I.O.N. - the Chemistry hub - Centers of Excellence Portal - [[Technetium|Technetium - the element made before found]] - the canon's patron - and Technitium, the School - [Transuranium element](https://en.wikipedia.org/wiki/Transuranium_element) - neptunium as the first of the human-synthesized actinides - [Nuclear transmutation](https://en.wikipedia.org/wiki/Nuclear_transmutation) - creation of neptunium via neutron bombardment ## Vocational-Technical Semiotics The element speaks the canon's shared signs: the periodic table cell (Np, group f, period 7), isotope notation, and hazard pictograms ghs where handling demands it. ## Sources Infobox: [en.wikipedia.org/wiki/List_of_chemical_elements](https://en.wikipedia.org/wiki/List_of_chemical_elements) (fetched 2026-07-08); etymology per the same table's notes. Story sources to be added at enrichment. ## Navigation - Canon: Elements Canon index - neighbors by Z: [[Uranium|Uranium (92)]] - [[Plutonium|Plutonium (94)]] - R.E.A.C.T.I.O.N. - Centers of Excellence ## Wikipedia : Wikitube **Strict pair:** [Wikipedia](https://en.wikipedia.org/wiki/Neptunium) : [Wikitube](https://en.wikitube.io/wiki/Neptunium) ## Previous hub tags Tree parents: [[Helium]] · [[Hydrogen]] · [[Oxygen]]. Legacy hubs: none. --- *Sources: 1 legacy note. Minted wave 1, 2026-07-30 (v1.6 order).*