Cobalt(II) bromide

Structure of cobalt(II) bromide tetrahydrate

Crystal structure of cobalt(II) bromide

Anhydrous cobalt(II) bromide in a vial

Identifiers

CAS Number

* 7789-43-7 Y

3D model (JSmol)

* Interactive image

ChemSpider |

* 23012 Y

EC Number |

* 232-166-7

PubChem CID

* 24610

RTECS number |

* GF9595000

UNII |

* 7M7RX75BAL Y

UN number | 3077

InChI

* InChI=1S/2BrH.Co/h2*1H;/q;;+2/p-2 Y

Key: BZRRQSJJPUGBAA-UHFFFAOYSA-L Y

* InChI=1/2BrH.Co/h2*1H;/q;;+2/p-2

Key: BZRRQSJJPUGBAA-NUQVWONBAJ

SMILES

* [Co](Br)Br

Properties

Chemical formula

| CoBr2, CoBr2.6H2O, CoBr2.2H2O
Molar mass | 218.7412 g/mol (anhydrous)
326.74 g/mol (hexahydrate)
Appearance  | Bright green crystals (anhydrous)
Red-purple crystals (hexahydrate)
Density | 4.909 g/cm3 (anhydrous)
2.46 g/cm3 (hexahydrate)
Melting point |  678 °C (1,252 °F; 951 K) (anhydrous)
47 °C (hexahydrate)

Solubility in water

| anhydrous:
66.7 g/100 mL (59 °C)
68.1 g/100 mL (97 °C)

* * *

hexahydrate:
113.2 g/100 mL (20 °C)
Solubility | 77.1 g/100 mL (ethanol, 20 °C)
58.6 g/100 mL (methanol, 30 °C)
soluble in methyl acetate, ether, alcohol, acetone

Magnetic susceptibility (χ)

| +13000·10−6 cm3/mol
Structure

Crystal structure

| Rhombohedral, hP3, SpaceGroup = P-3m1, No. 164

Coordination geometry

| octahedral
Hazards
Safety data sheet | Fisher Scientific
GHS pictograms |
GHS Signal word | Danger

GHS hazard statements

| H302, H312, H315, H317, H319, H332, H334, H335, H350

GHS precautionary statements

| P201, P202, P261, P264, P270, P271, P272, P280, P281, P285, P301+312, P302+352, P304+312, P304+340, P304+341, P305+351+338, P308+313, P312, P321, P322, P330, P332+313, P333+313, P337+313, P342+311
NFPA 704 (fire diamond)  |

Flash point | Non-flammable
Lethal dose or concentration (LD, LC):

LD50 (median dose)

| 406 mg/kg (oral, rat)
Related compounds

Other anions

| cobalt(II) fluoride
cobalt(II) chloride
cobalt(II) iodide

Other cations

| iron(II) bromide
nickel(II) bromide

Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Y verify (what is YN ?)
Infobox references

Cobalt(II) bromide (CoBr2) is an inorganic compound. In its anhydrous form, it is a green solid that is soluble in water, used primarily as a catalyst in some processes.

## Contents

* 1 Properties
* 2 Preparation and reactions
* 3 Safety
* 4 References

## Properties

When anhydrous, cobalt(II) bromide appears as green crystals. It is hygroscopic and eventually forms the hexahydrate in air,[1] which appears as red-purple crystals. The hexahydrate loses four water of crystallization molecules at 100 °C forming the dihydrate:

CoBr2·6H2O → CoBr2·2H2O + 4 H2O

Further heating to 130 °C produces the anhydrous form:

CoBr2·2H2O → CoBr2 \+ 2 H2O

The anhydrous form melts at 678 °C.[2][3] At higher temperatures, cobalt(II) bromide reacts with oxygen, forming cobalt(II,III) oxide and bromine vapor.

The tetrahydrate is molecular, with the formula trans-[CoBr2(H2O)4].[4]

## Preparation and reactions

Cobalt(II) bromide can be prepared as a hydrate by the reaction of cobalt hydroxide with hydrobromic acid:

Co(OH)2 \+ 2HBr → CoBr2·6H2O

The classical coordination compound bromopentaamminecobalt(III) bromide is prepared by oxidation of an aqueous solution of cobalt(II) bromide and ammonia.[5]

2 CoBr2 \+ 8 NH3 \+ 2 NH4Br + H2O2 → 2 [Co(NH3)5Br]Br2 \+ 2 H2O

Triphenylphosphine complexes of cobalt(II) bromide have been used as a catalysts in organic synthesis.[citation needed]

## Safety

Exposure to large amounts of cobalt(II) can cause cobalt poisoning.[6] Bromide is also mildly toxic.

## References

1. ↑ Perry, Dale L. (2011). Handbook of Inorganic Compounds (2nd ed.). Boca Raton: Taylor & Francis. pp. 130. ISBN 978-1-4398-1461-1. OCLC 587104373. https://www.worldcat.org/oclc/587104373.
2. ↑ Cobalt Bromide Supplier & Tech Info American Elements
3. ↑ WebElements Periodic Table of the Elements
4. ↑ Waizumi, Kenji; Masuda, Hideki; Ohtaki, Hitoshi (1992). "X-ray Structural Studies of FeBr2·4H2O, CoBr2·4H2O, NiCl2·4H2O and CuBr2·4H2O. Cis/Trans Selectivity in Transition Metal(II) Dihalide Tetrahydrate". Inorganica Chimica Acta 192 (2): 173–181. doi:10.1016/S0020-1693(00)80756-2.
5. ↑ Diehl, Harvey; Clark, Helen; Willard, H. H.; Bailar, John C. (1939). "Bromopentamminocobalti Bromide". Inorganic Syntheses. Inorganic Syntheses. 1. pp. 186. doi:10.1002/9780470132326.ch66. ISBN 978-0-470-13232-6.
6. ↑ "Cobalt Bromide (OUS)". http://www.chrismanual.com/C/COB.pdf.

* v
* t
* e

Cobalt compounds

* CoBr2
* Co(CN)2
* CoCO3
* CoC2O4
* CoCl2
* CoCl3
* Co(ClO3)2
* CoF2
* CoF3
* CoI2
* Co(NO3)2
* Co(NO3)3
* CoO
* Co(OH)2
* CoS
* CoSO4
* CoSe
* Co2O3
* Co2P
* Co3O4
* Co3(PO4)2
* Co(Ac)2

* v
* t
* e

Bromine compounds

* AgBr
* AlBr3
* AmBr3
* AsBr3
* AuBr3
* BBr3
* B2Br4
* BaBr2
* BeBr2
* BiBr3
* BrCl
* CsBr
* BrF3
* BrF5
* HBr
* IBr
* KBr
* LiBr
* BrN3
* NaBr
* BrO2
* RbBr
* TlBr
* CaBr2
* CdBr2
* CoBr2
* CuBr2
* EuBr2
* FeBr2
* GeBr2
* HgBr2
* Hg2Br2
* MgBr2
* MnBr2
* NiBr2
* Br2O
* Br2O3
* Br2O5
* PbBr2
* PdBr2
* PtBr2
* RaBr2
* S2Br2
* Se2Br2
* SnBr2
* SrBr2
* TeBr2
* YbBr2
* ZnBr2
* CeBr3
* CrBr3
* CsBr3
* DyBr3
* ErBr3
* EuBr3
* FeBr3
* GaBr3
* GdBr3
* HoBr3
* InBr
* InBr3
* IrBr3
* LaBr3
* LuBr3
* MoBr3
* NBr3
* NdBr3
* PBr3
* PrBr3
* ReBr3
* SbBr3
* SmBr3
* TbBr3
* TmBr3
* UBr3
* VBr3
* YBr3
* YbBr3
* GeBr4
* HfBr4
* PbBr4
* SeBr4
* SiBr4
* SnBr4
* TeBr4
* ThBr4
* TiBr4
* UBr4
* WBr4
* ZrBr4
* NbBr5
* PBr5
* TaBr5
* UBr5
* WBr5
* CBr4
* CrBr2
* DyBr2
* HfBr2
* HfBr3

Chemical formulas

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*[CID]: Compound ID
*[H302]: Harmful if swallowed
*[H312]: Harmful in contact with skin
*[H315]: Causes skin irritation
*[H317]: May cause an allergic skin reaction
*[H319]: Causes serious eye irritation
*[H332]: Harmful if inhaled
*[H334]: May cause allergy or asthma symptoms of breathing difficulties if inhaled
*[H335]: May cause respiratory irritation
*[H350]: May cause cancer
*[P201]: Obtain special instructions before use
*[P202]: Do not handle until all safety precautions have been read and understood
*[P261]: Avoid breathing dust/fume/gas/mist/vapours/spray
*[P264]: Wash … thoroughly after handling
*[P270]: Do not eat, drink or smoke when using this product
*[P271]: Use only outdoors or in a well-ventilated area
*[P272]: Contaminated work clothing should not be allowed out of the workplace
*[P280]: Wear protective gloves/protective clothing/eye protection/face protection
*[P281]: Use personal protective equipment as required
*[P285]: In case of inadequate ventilation wear respiratory protection
*[P301+312]: IF SWALLOWED: Call a POISON CENTER or doctor/physician if you feel unwell
*[P302+352]: IF ON SKIN: Wash with soap and water
*[P304+312]: IF INHALED: Call a POISON CENTER or doctor/physician if you feel unwell
*[P304+340]: IF INHALED: Remove victim to fresh air and keep at rest in a position comfortable for breathing
*[P304+341]: IF INHALED: If breathing is difficult, remove victim to fresh air and keep at rest in a position comfortable for breathing
*[P305+351+338]: IF IN EYES: Rinse continuously with water for several minutes. Remove contact lenses if present and easy to do – continue rinsing
*[P308+313]: IF exposed or concerned: Get medical advice/attention
*[P312]: Call a POISON CENTER or doctor/physician if you feel unwell
*[P321]: Specific treatment (see … on this label)
*[P322]: Specific measures (see … on this label)
*[P330]: Rinse mouth
*[P332+313]: If skin irritation occurs: Get medical advice/attention
*[P333+313]: If skin irritation or a rash occurs: Get medical advice/attention
*[P337+313]: Get medical advice/attention
*[P342+311]: Call a POISON CENTER or doctor/physician
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