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Cobalt(II) nitrate

chemical compound

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Record originEnglish Wikipedia
Text licenseCC BY-SA 4.0
Source revisionMar 11, 2026
Entity authorityQ414860 ↗
Source-derived summary

Cobalt nitrate is the inorganic compound with the formula Co(NO3)2.xH2O. It is a cobalt(II) salt. The most common form is the hexahydrate Co(NO3)2·6H2O, which is a red-brown deliquescent salt that is soluble in water and other polar solvents.

Composition and structures

As well as the anhydrous compound Co(NO3)2, several hydrates of cobalt(II) nitrate exist. These hydrates have the chemical formula Co(NO3)2·nH2O, where n = 0, 2, 4, 6.

Anhydrous cobalt(II) nitrate adopts a three-dimensional polymeric network structure, with each cobalt(II) atom approximately octahedrally coordinated by six oxygen atoms, each from a different nitrate ion. Each nitrate ion coordinates to three cobalts. The dihydrate is a two-dimensional polymer, with nitrate bridges between Co(II) centres and hydrogen bonding holding the layers together. The tetrahydrate consists of discrete, octahedral [(H2O)4Co(NO3)2] molecules. The hexahydrate is better described as hexaaquacobalt(II) nitrate, [Co(OH2)6][NO3]2, as it consists of discrete [Co(OH2)6]2+ and [NO3]− ions. Above 55 °C, the hexahydrate converts to the trihydrate and at higher temperatures to the monohydrate.

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The public source identifies “Cobalt(II) nitrate” as chemical compound. This brief keeps that definition visible, then builds a research path around Cobalt, nitrate and chemical.

Editorial reviewUseful for establishing the present vocabulary of the subject while preserving a route back to the evidence on which that vocabulary rests. The current 162-word lead offers orientation but no explicit four-digit date, so chronology should not be assumed. The selected authority fields contribute no independent date. Its value is orientation rather than verdict, with Cobalt, nitrate and chemical providing the first useful test.
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This entry incorporates text from “Cobalt(II) nitrate” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.