Cobalt(II) chloride is the chemical compound with the formula CoCl₂, although the term is used also to refer to the hexahydrate, which is a different chemical compound. CoCl₂ is blue, and CoCl₂·6H₂O is deep magenta. Because of this dramatic color change and the ease of the hydration/dehydration reaction, "cobalt chloride" is used as an indicator for water. The magenta hexahydrate is probably the most familiar cobalt compound in the laboratory. CAS registry numbers are unique numerical identifiers for chemical compounds, polymers, biological sequences, mixtures and alloys. ... In physics, density is mass m per unit volume V. For the common case of a homogeneous substance, it is expressed as: where, in SI units: ρ (rho) is the density of the substance, measured in kg·m-3 m is the mass of the substance, measured in kg V is... In the physical sciences, a phase is a set of states of a macroscopic physical system that have relatively uniform chemical composition and physical properties (i. ... It has been suggested that this article or section be merged with Solution. ... This article describes water from a scientific and technical perspective. ... The melting point of a crystalline solid is the temperature at which it changes state from solid to liquid. ... Italic text This article is about the boiling point of liquids. ... The coordination geometry of an atom is the geometrical pattern formed by its neighbors in a molecule or a crystal. ... An octahedron (plural: octahedra) is a polyhedron with eight faces. ... Enargite crystals In mineralogy and crystallography, a crystal structure is a unique arrangement of atoms in a crystal. ... Cadmium chloride is a white crystalline compound of cadmium and chlorine, with the formula CdCl2. ... An example MSDS in a US format provides guidance for handling a hazardous substance and information on its composition and properties. ... Council Directive 67/548/EEC of 27 June 1967 on the approximation of laws, regulations and administrative provisions relating to the classification, packaging and labelling of dangerous substances (as amended) is the main European Union law concerning chemical safety. ... The hazard symbol for carcinogenic chemicals in the Globally Harmonized System. ... NFPA 704 is a standard maintained by the U.S. National Fire Protection Association. ... R-phrases are defined in Annex III of European Union Directive 67/548/EEC: Nature of special risks attributed to dangerous substances and preparations. ... S-phrases are defined in Annex IV of European Union Directive 67/548/EEC: Safety advice concerning dangerous substances and preparations. ... The flash point of a flammable liquid is the lowest temperature at which it can form an ignitable mixture with air. ... RTECS, also known as Registry of Toxic Effects of Chemical Substances, is a database of toxicity information compiled from the open scientific literature that is available for charge. ... The refractive index (or index of refraction) of a medium is a measure for how much the speed of light (or other waves such as sound waves) is reduced inside the medium. ... The relative dielectric constant of a material under given conditions is a measure of the extent to which it concentrates electrostatic lines of flux. ... Ultraviolet-Visible Spectroscopy or Ultraviolet-Visible Spectrophotometry (UV/ VIS) involves the spectroscopy of photons (spectrophotometry). ... Infrared spectroscopy (IR Spectroscopy) is the subset of spectroscopy that deals with the IR region of the EM spectrum. ... It has been suggested that NMR Data Processing be merged into this article or section. ... Mass spectrometry (also known as mass spectroscopy (deprecated)[1] or informally, mass-spec and MS) is an analytical technique used to measure the mass-to-charge ratio of ions. ... An electrostatic potential map of the nitrate ion (NO3−). Areas coloured red are lower in energy than areas colored yellow An ion is an atom or group of atoms which have lost or gained one or more electrons, making them negatively or positively charged. ... Cobalt(II) fluoride has formula CoF2. ... Cobalt(II) oxide is a blackish gray powder used extensively in the ceramics industry as an additive to create blue colored glazes and enamels as well as in the chemical industry for producing cobalt(II) salts. ... An electrostatic potential map of the nitrate ion (NO3−). Areas coloured red are lower in energy than areas colored yellow An ion is an atom or group of atoms which have lost or gained one or more electrons, making them negatively or positively charged. ... Rhodium(III) chloride is the end-point of the separation of rhodium from the other platinum group metals, and hence the starting material for most rhodium chemistry. ... Iridium(III) chloride is the starting material for most iridium chemistry. ... In chemistry, the standard state of a material is its state at 1 bar (100 kilopascals) and 25 degrees Celsius (298. ... A chemical compound is a chemical substance of two or more different chemically bonded chemical elements, with a fixed ratio determining the composition. ... wikipedia sucks big balls For other uses, see Cobalt (disambiguation). ... General Name, Symbol, Number chlorine, Cl, 17 Chemical series halogens Group, Period, Block 17, 3, p Appearance yellowish green Standard atomic weight 35. ... This article describes water from a scientific and technical perspective. ...

Aqueous solutions of both CoCl₂ and the hydrate contain the species trans-[CoCl₂(H₂O)₄]. This is maintained in the solid state by the hexahydrate, the remaining two water molecules in its formula unit being water of crystallization. This species dissolves readily in water and alcohol. It has the interesting property that a concentrated aqueous solution is red at room temperature, but becomes blue when heated.^[1] CoCl₂·6H₂O is deliquescent and the anhydrous salt CoCl₂ is hygroscopic, readily converting to the hydrate. Water of crystallization (alt. ... Ethanol, also known as ethyl alcohol, drinking alcohol or grain alcohol, is a flammable, colorless, slightly toxic chemical compound, and is best known as the alcohol found in alcoholic beverages. ... Drinking water This article focuses on water as we experience it every day. ... Deliquescent materials are substances (mostly salts) which have a strong affinity for moisture and will absorb relatively large amount of water from the atmosphere if exposed to it, forming a liquid solution. ... A hygroscopic substance is a substance that absorbs water readily from its surroundings. ...

Chemical properties

CoCl₂·6H₂O and CoCl₂ are weak Lewis acids that convert to many other complexes. These cobalt (II) complexes are usually either octahedral or tetrahedral. Examples include: In chemistry, a Lewis acid can accept a pair of electrons and form a coordinate covalent bond, after the American chemist Gilbert Lewis. ... An octahedron (plural: octahedra) is a polyhedron with eight faces. ... A tetrahedron (plural: tetrahedra) is a polyhedron composed of four triangular faces, three of which meet at each vertex. ...

CoCl₂·6H₂O + 4 C₅H₅N → CoCl₂(C₅H₅N)₄ + 6 H₂O

CoCl₂·6H₂O + 2 P(C₆H₅)₃ → CoCl₂{P(C₆H₅)₃}₂ + 6 H₂O

CoCl₂ + 2 [(C₂H₅)₄N]Cl → [(C₂H₅)₄N)]₂[CoCl₄]^[2]

Otherwise, aqueous solutions of cobalt(II) chlorides behave like other cobalt(II) salts, such as precipitating CoS upon treatment with H₂S. Pyridine is a chemical compound with the formula C5H5N. It is a liquid with a distinctively putrid odour. ... Triphenylphosphine (in Europe: triphenylphosphane) is a common organophosphorus compound with the formula P(C6H5)3 - often abbreviated to PPh3 or Ph3P. It is widely used in the synthesis of organic and organometallic compounds. ... Hydrogen sulfide (hydrogen sulphide in British English), H2S, is a colorless, toxic, flammable gas that is responsible for the foul odor of rotten eggs and flatulence. ...

Co(III) derivatives

In the presence of ammonia or amines, cobalt(II) is readily oxidised by atmospheric oxygen to give a variety of cobalt(III) complexes. For example: Ammonia is a compound with the formula NH3. ... The general structure of an amine Amines are organic compounds and a type of functional group that contain nitrogen as the key atom. ... Illustration of a redox reaction Redox (shorthand for oxidation/reduction reaction) describes all chemical reactions in which atoms have their oxidation number (oxidation state) changed. ... General Name, Symbol, Number oxygen, O, 8 Chemical series nonmetals, chalcogens Group, Period, Block 16, 2, p Appearance colorless (gas) very pale blue (liquid) Standard atomic weight 15. ...

4 CoCl₂·6H₂O + 4 [NH₄]Cl + 20 NH₃ + O₂ → 4 [Co(NH₃)₆]Cl₃ + 26 H₂O

The reaction is often performed in the presence of charcoal as a catalyst, or hydrogen peroxide is employed in place of air. Other highly basic ligands including carbonate, acetylacetonate, and oxalate induce the formation of Co(III) derivatives. Simple carboxylates and halides do not. Ammonium chloride or Sal Ammoniac (chemically ammonium chloride (NH4Cl); also salmiac, nushadir salt, zalmiak, sal armagnac, sal armoniac, salmiakki, salmiak and salt armoniack) is, in its pure form, a clear white water-soluble crystalline salt with a biting, slightly sour taste. ... Ammonia is a compound with the formula NH3. ... General Name, Symbol, Number oxygen, O, 8 Chemical series nonmetals, chalcogens Group, Period, Block 16, 2, p Appearance colorless (gas) very pale blue (liquid) Standard atomic weight 15. ... Cobalt(III) hexammine chloride is the chemical compound with the formula [Co(NH3)6]Cl3. ... This article describes water from a scientific and technical perspective. ... General Name, symbol, number carbon, C, 6 Chemical series nonmetals Group, period, block 14, 2, p Appearance black (graphite) colorless (diamond) Standard atomic weight 12. ... Hydrogen peroxide (H2O2) is a very pale blue liquid which appears colourless in a dilute solution, slightly more viscous than water. ... In organic chemistry, a carbonate is a salt of carbonic acid. ... R-phrases , S-phrases , , , Flash point 34 °C Autoignition temperature 340 °C Explosive limits 2. ... An oxalate (called also: ethanedioate) is a salt or ester of oxalic acid. ...

Unlike Co(II) complexes, Co(III) complexes are very slow to exchange ligands, so they are said to be kinetically inert. The German chemist Alfred Werner was awarded the Nobel prize in 1913 for his studies on a series of these cobalt(III) compounds, work that led to an understanding of the structures of such coordination compounds. Synthesis of copper(II)-tetraphenylporphine, a metal complex, from tetraphenylporphine and copper(II) acetate monohydrate. ... In chemistry, a ligand is an atom, ion, or molecule (see also: functional group) that generally donates one or more of its electrons through a coordinate covalent bond to, or shares its electrons through a covalent bond with, one or more central atoms or ions (these ligands act as a... Alfred Werner (December 12, 1866 - November 15, 1919) was a German Nobel prize-winning chemist. ... Nobel Prize medal. ... Synthesis of copper(II)-tetraphenylporphine, a metal complex, from tetraphenylporphine and copper(II) acetate monohydrate. ...

Instability of CoCl₃

The existence of cobalt(III) chloride, CoCl₃, is disputed, although it is listed in some compendia.^[3] An authoritative monograph^[4] states, "Apart from CoF₃, the only known halides of cobalt are the dihalides." The reduction potential for Co³⁺ + e^- → Co²⁺ is more favorable (+1.92 V) than the reduction Cl₂ to Cl^- (+1.36 V). This analysis suggests also that the naked cation Co³⁺ would oxidize chloride to chlorine, precluding the formation of CoCl₃. Stated differently, CoCl₂ is unreactive toward Cl₂. This analysis changes considerably in the presence of ligands of Lewis basicity superior to chloride's, such as amines. Cobalt(III) fluoride is a chemical compound with the formula CoF3. ...

Preparation

Cobalt(II) chloride can be prepared in its anhydrous form from cobalt metal and chlorine gas: wikipedia sucks big balls For other uses, see Cobalt (disambiguation). ... General Name, Symbol, Number chlorine, Cl, 17 Chemical series halogens Group, Period, Block 17, 3, p Appearance yellowish green Standard atomic weight 35. ...

Co(s) + Cl₂(g) → CoCl₂(s)

The hydrated form can be prepared from cobalt(II) hydroxide or cobalt(II) carbonate and hydrochloric acid. wikipedia sucks big balls For other uses, see Cobalt (disambiguation). ... For other uses, see Solid (disambiguation). ... General Name, Symbol, Number chlorine, Cl, 17 Chemical series halogens Group, Period, Block 17, 3, p Appearance yellowish green Standard atomic weight 35. ... This article does not cite any references or sources. ... The chemical compound hydrochloric acid is the aqueous (water-based) solution of hydrogen chloride gas (HCl). ...

Uses

A common use for cobalt(II) chloride is for the detection of moisture, for example in drying agents such as silica gel. In the US calcium sulfate is sold as a drying agent under the trade name Drierite. When cobalt(II) chloride is added as an indicator, the drying agent is blue when still active, pink when exhausted, corresponding to the anhydrous and hydrated forms of CoCl₂ respectively. Similarly, paper impregnated with cobalt chloride, known as "cobalt chloride paper" is likewise used to detect the presence of water. A dessicant is a hygroscopic substance that induces or sustains a state of dryness (desiccation) in its local vicinity in a moderately-well sealed container. ... Beads of silica gel Silica gel is a granular, porous form of silica made synthetically from sodium silicate. ... Calcium sulfate is a common laboratory and industrial chemical. ...

In the laboratory, cobalt(II) chloride serves as a standard precursor for the synthesis of other cobalt compounds. For example, the reaction of 1-norbonyllithium with CoCl₂ produces a brown, thermally stable cobalt(IV) tetralkyl^[5] — the only compound of its kind for which the detailed structure is fully known^[4]: Image File history File links Download high resolution version (1200x428, 6 KB)Preparation of tetranorbornylcobalt This image has been released into the public domain by its creator and original copyright holder. ...

Reaction of anhydrous CoCl₂ with sodium cyclopentadienylide in THF gives the black sandwich compound cobaltocene. This 19-electron species is a good reducing agent, being readily oxidised to the yellow 18-electron cobaltacenium cation, which is isoelectronic with ferrocene. Tetrahydrofuran, also known as THF, hydrofuran, oxolane, oxacyclopentane, or furanidine, is a heterocyclic organic compound. ... Space-filling model of ferrocene, the archetypal sandwich compound A sandwich compound in organometallic chemistry is any chemical compound containing a metal atom sandwiched between two arene units. ... Cobaltocene, Co(C5H5)2, also known as bis(cyclopentadienyl)cobalt(II), belongs to a group of organometallic compounds called metallocenes which consist of a metal ion sandwiched between two cyclopentadienyl (Cp) rings. ... The 18-electron rule is a rule of thumb used primarily in transition metal chemistry for characterizing and predicting the stability of metal complexes. ... Two or more molecular entities (atoms, molecules, ions) are described as isoelectronic if they have the same number of valence electrons and the same structure (number and connectivity of atoms), but may differ in the elements involved. ... Ferrocene is the chemical compound with the formula Fe(C5H5)2. ...

References

1. ^ The Merck Index, 7th edition, Merck & Co, Rahway, New Jersey, USA, 1960.
2. ^ Gill, N. S. and Taylor, F. B., "Tetrahalo Complexes of Dipositive Metals in the First Transition Series", Inorganic Syntheses, 1967, volume 9, pages 136-142.
3. ^ Handbook of Chemistry and Physics, 71st edition, CRC Press, Ann Arbor, Michigan, 1990.
4. ^ ^{a b} Greenwood, N. N.; Earnshaw, A. (1997). Chemistry of the Elements, 2nd Edition, Oxford:Butterworth-Heinemann. ISBN 0-7506-3365-4. 
5. ^ Erin K. Byrne, Darrin S. Richeson and Klaus H. Theopold (1986). "Tetrakis(1-norbornyl)cobalt, a low spin tetrahedral complex of a first row transition metal". J. Chem. Soc., Chem. Commun.: 1491 - 1492. DOI:10.1039/C39860001491. 

Chemical Communications, known as ChemComm, is a peer-reviewed scientific journal. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ...

External links

• International Chemical Safety Card 0783
• National Pollutant Inventory - Cobalt fact sheet
• IARC Monograph "Cobalt and Cobalt Compounds"