chemproject.pdf

Analysis of the Colors of Coordination Complexes By Matt Goodstein

Mr. Swenson NEST+m Periods 7 and 8

6-5-13

Introduction

Coordination complexes are a highly important type of chemical compound. Two things are required to form a coordination complex: a metal cation, preferably a transition metal, and several molecules or anions with either lone pairs or double bonds. One atom donating two electrons to another atom forms what is referred to as a coordinate bond. Unlike ionic compounds, the metal cation will bind to more ligands than would be suggested by its oxidation state; some coordination compounds have a net negative charge. Coordination complexes can either be positive, negative, or neutral. Another interesting fact about coordination complexes is that they can display chirality. This is important, as they were the first chiral molecules to be discovered that did not contain carbon. Some coordination complexes, called chelates, have the central atom bonded more than once to a single molecule. An example of a molecule that can form chelates is ethylenediamine. Ethylenediamine is composed of a nitrogen atom bonded to two hydrogen atoms and a carbon atom, which is bonded to two hydrogen atoms and another carbon atom, which is bonded to two more hydrogen atoms and another nitrogen atom, which is bonded to two hydrogen atoms. The two lone pairs of the nitrogen atoms bond to the same metallic ion, and are connected by the two carbon atoms.

A property of coordination complexes is that they are very colorful. This property is due to electron absorption and emission. Because of this property, coordination complexes have been used in certain pigments, such as Prussian Blue, which is a coordination complex with an iron cation and six cyanide ions. One of the interesting things about Prussian Blue is that it is relatively nontoxic; the cyanide ligands do not disassociate from the iron atom when placed in water. This demonstrates that coordination complexes are not just a special kind of ionic compound. In addition to this, coordination complexes are also used in multiple chemical applications. For example, ferrocene and cisplatin, two coordination complexes, have cancer-curing properties. Hemoglobin uses coordination complexes to transport oxygen throughout the human body; the oxygen molecule coordinates to the iron in hemoglobin. An important ligand that is used in biochemistry is poryphin. Poryphin is a ring-shaped ligand that coordinates a metal atom using four nitrogen atoms in the center of the ring. Examples of poryphins are hemoglobin and chlorophyll. One use f coordination complexes in medicine is chelation therapy. Chelation therapy is when chelates are used to sequester toxic metal cations within the body, by chelating them. Coordination complexes can also explain the toxicity of certain ions; cyanide works by forming complexes with metal atoms in the electron transport chain, and carbon monoxide functions by binding to hemoglobin,

Review of Related Literaturre

Coordination complexes are molecules which are formed by multiple molecules, ions, or atoms with either lone pairs or double bonds (or even single bonds, in some rare cases) attaching to a cation, especially a metal cation. These complexes have many interesting properties. The one that is the focus of this experiment is the vivid coloration that many coordination complexes exhibit. As is widely known, within an atom, electrons can absorb photons by jumping from one energy level of the atom to another. This is an inconsequential property in most chemical compounds. However, coordination complexes exacerbate this property. Transition-metal ions have some of their electrons in D orbitals. Some of the d-orbitals are closer to the ligands than the other ones.. The d-d-orbitals that are more repelled by the ligands have a higher energy level. The energy of the band gap can also cause electrons that would normally not be paired to be paired, as the energy needed to put two electrons in the same orbital is less than the band gap, in certain cases. The gap between the energy levels of the closer and the further set of d-orbitals is referred to as the band gap; this is what creates the color. When light strikes an electron, if the energy of the photon is equal to the energy of the band gap, the photon is absorbed. Ordinarily, when an electron is excited, it changes its principal energy level. However, in a coordination complex, it changes its If it is not, the photons are reflected. This causes the light reflected by the coordination complex to have the wavelength that corresponds to the energy of the band gap removed from its spectrum. This makes the coordination complex appear as the complementary color of the absorbed light.

The energy of the band gap is based on multiple factors. The two most important factors are the strength of the ligands and the splitting factors of the central cation. Some ligands are more repellant of the electrons than others. This leads to the wavelength of the absorbed photons being longer for stronger ligands. Carbon monoxide ligands are the strongest, ammonia ligands are in the middle, and iodide ligands are the weakest. When different ligands are involved, the different configurations of the ligands can result in different band gaps; for example, the trans and cis isomers of [Co(NH3)4Cl2]+ have different colors. In addition, the cation coordinated affects the band gap. The more positive the charge of the cation is, the larger the band gap will be. In addition, the larger the zeff of the cation is, the larger the band gap will be. The specific type of coordination complex that will be studied in this project are cobalt

coordination complexes, specifically with water, ammonia, and chlorine ligands. Cobalt complexes were among the first coordination complexes studied. Alfred Werner, one of the first developers of

(III) in the presence of ammonia. Once the cobalt is in the (III) oxidation state, it is very slow to change its ligands. Charcoal is usually used to catalyze this process. The reason that cobalt has been chosen for this experiment is because it exhibits a wide range of coloration and coordination complexes. It can have multiple coordination complexes with many different combinations of NH3 and Cl- ligands. As previously stated, these combinations can have wildly different colors, even with the same chemical composition.

There are multiple ways to synthesize coordination complexes. Cobalt hexahydrate is easy to synthesize; once it is poured into water, it forms a hydrate. To form other coordination complexes requires a bit more work. In order to form octahedral ammonia coordination complexes, the cobalt (II) needs to be oxidized to cobalt (III). This can be done using multiple methods. The first method is adding hydrogen peroxide and hydrogen chloride to the solution. As is well known, hydrogen peroxide is a powerful oxidizer in acidic solution. When it is added to the cobalt chloride, the hydrogen peroxide and hydrogen ions are reduced to water. In addition, the chloride ions from the hydrogen chloride are left behind and are added to the solution. After that, it is necessary to catalyze the addition of the ammonia to the cobalt cation. To do this, multiple reagants are required. First, an excess of ammonia is required. This is accomplished by adding ammonia to the solution. In addition to this, ammonium chloride may also be added. The addition of the ammonium ions shifts the chemical equilibrium of the ammonium hydroxide to the ammonia side, increasing the amount of ammonia ions inn the solution

this, there is a 3-form resonance structure; two with each carbon atom being bonded to the central cation, and one with the two carbon atoms being bonded together using the central pi bond.

Materials:

Hydrogen Peroxide Cobalt Chloride Sodium Hydroxide Hydrogen Chloride Distilled Water Ammonium Chloride Ammonium hydroxide Sodium Chloride 4 beakers

Methods:

Synthesizing [(H2O)3(OH-)3 Co]

Pour cobalt hexahydrate into a sodium hydroxide solution and mix it with hydrogen peroxide. Synthesizing [(H2O)4(OH-)2Co]

Pour cobalt hexahydrate into a sodium hydroxide solution. Synthesizing [(NH3)6Co]3+

Pour cobalt hexahydrate into a solution of ammonia (to provide the ammonia ligands) and mix it with ammonium chloride (to Increase the concentration of NH3 by shifting the chemical equilibrium away from NH4+) and hydrogen peroxide (to oxidize the cobalt (II) to cobalt (III))

Synthesizing [(H2O)4Cl2Co]

Place cobalt hydroxide crystals in HCl (to provide the Cl- _{ligands and to dissolve the hydroxide ligands)}

1. Pour water into a beaker, and pour cobalt chloride into that beaker. 2. Fill the remaining beakers with each of the following:

3. Pour cobalt chloride solution into each of the beakers. 4. Pour HCl into the beaker containing the cobalt hydroxide.

Results:

Coordination complex Color [(H2O)3(OH-)3 Co] Dark brown [(H2O)4(OH-)2Co] Blue

Conclusion:

The compounds synthesized exhibited a wide variety of colors. In this discussion, the cause of these colors will be determined.

Color of [(NH3)6Co]3+

This coordination complex was synthesized using ammonium chloride, ammonium hydroxide, hydrogen peroxide, and cobalt chloride. All of these elements were poured into a beaker and mixed together. The actual color of [(NH3)6Co]3+ is closer to orange rather than the color observed. From this, we can conclude that the synthesis may have been unsuccessful. There may have been an observed change in the color; however, the results are more consistent with cobalt(III) hydroxide than with However, when placed in a solution, hexamine cobalt (III) undergoes various reactions with the water, and can appear brown. Multiple coordination complexes can form, and a wide variety of wavelengths can be observed, which can appear brown.

Color of the hydroxide compounds

Dihydroxy cobalt(II) is the color predicted by the literature. Its blue color suggests that it absorbs a wavelength somewhere in the vicinity of orange. When HCl is poured into it, it turns green, redshifting. We can assume that the hydrogen ions neutralized the hydroxide ions, and the hydroxide ions were replaced with chloride ions. Since chloride is a significantly weaker ligand than hydroxide ligands or water , we can assume that the wavelength absorbed was in the red range, turning the compound green. When it is oxidized to cobalt (III), it turns brown. We can assume that it is absorbing a higher wavelength, as predicted by the fact that the positivity of the central cation is increasing, but the dark color suggests that there are a wide variety of wavelengths being absorbed. We can attribute this to a certain

phenomenon. There are two isomers of trihydroxy cobalt (III): fac and mer, which correspond to two ligands being opposite each other and one between them, and the three ligands all adjacent to each other. However, cobalt (II) hydroxide has the same number of isomers (cis and trans), and appears not to absorb the amount of wavelengths that cobalt (III) hydroxide absorbs. Although we can assume that all

Material Safety Data

Sheet

Cobalt Chloride Solution MSDS

Section 1: Chemical Product and Company Identification

Catalog Codes: SLC3259

CAS#: Mixture.

RTECS: Not applicable.

TSCA: TSCA 8(b) inventory: Water; Hydrochloric acid; Cobalt chloride hexahydrate

CI#: Not available.

Synonym: Cobalt Chloride Solution

Chemical Name: Not applicable.

Chemical Formula: Not applicable.

Contact Information: Sciencelab.com, Inc.

14025 Smith Rd. Houston, Texas 77396 US Sales: 1-800-901-7247

International Sales: 1-281-441-4400

Order Online: ScienceLab.com

CHEMTREC (24HR Emergency Telephone), call:

1-800-424-9300

International CHEMTREC, call: 1-703-527-3887

For non-emergency assistance, call: 1-281-441-4400

Section 2: Composition and Information on Ingredients

Name CAS # % by Weight

Water 7732-18-5 95.2

Hydrogen chloride 7647-01-0 3.63

Cobalt chloride hexahydrate 7791-13-1 1.2

Toxicological Data on Ingredients: Hydrogen chloride: GAS (LC50): Acute: 4701 ppm 0.5 hours [Rat]. Cobalt chloride

hexahydrate: ORAL (LD50): Acute: 766 mg/kg [Rat].

Section 3: Hazards Identification

Very hazardous in case of skin contact (irritant), of eye contact (irritant), of ingestion, . Hazardous in case of skin contact

or spray mist may produce tissue damage particularly on mucous membranes of eyes, mouth and respiratory tract. Skin

contact may produce burns. Inhalation of the spray mist may produce severe irritation of respiratory tract, characterized by

coughing, choking, or shortness of breath. Severe over-exposure can result in death. Inflammation of the eye is characterized

by redness, watering, and itching. Skin inflammation is characterized by itching, scaling, reddening, or, occasionally, blistering.

Potential Chronic Health Effects:

CARCINOGENIC EFFECTS: Classified 3 (Not classifiable for human.) by IARC [Hydrogen chloride]. MUTAGENIC EFFECTS:

Mutagenic for mammalian somatic cells. [Cobalt chloride hexahydrate]. Mutagenic for bacteria and/or yeast. [Cobalt chloride

p. 2

hexahydrate]. TERATOGENIC EFFECTS: Not available. DEVELOPMENTAL TOXICITY: Classified Reproductive system/

toxin/male [POSSIBLE] [Cobalt chloride hexahydrate]. The substance may be toxic to blood, lungs, upper respiratory tract,

skin, eyes, , teeth. Repeated or prolonged exposure to the substance can produce target organs damage. Repeated or

prolonged contact with spray mist may produce chronic eye irritation and severe skin irritation. Repeated or prolonged

exposure to spray mist may produce respiratory tract irritation leading to frequent attacks of bronchial infection. Repeated

exposure to a highly toxic material may produce general deterioration of health by an accumulation in one or many human

organs.

Section 4: First Aid Measures

Check for and remove any contact lenses. In case of contact, immediately flush eyes with plenty of water for at least 15

minutes. Cold water may be used. Get medical attention immediately.

Skin Contact:

In case of contact, immediately flush skin with plenty of water for at least 15 minutes while removing contaminated clothing

and shoes. Cover the irritated skin with an emollient. Cold water may be used.Wash clothing before reuse. Thoroughly clean

shoes before reuse. Get medical attention immediately.

Serious Skin Contact:

Wash with a disinfectant soap and cover the contaminated skin with an anti-bacterial cream. Seek immediate medical

attention.

Inhalation:

If inhaled, remove to fresh air. If not breathing, give artificial respiration. If breathing is difficult, give oxygen. Get medical

attention immediately.

Serious Inhalation:

Evacuate the victim to a safe area as soon as possible. Loosen tight clothing such as a collar, tie, belt or waistband. If

breathing is difficult, administer oxygen. If the victim is not breathing, perform mouth-to-mouth resuscitation. WARNING: It may

be hazardous to the person providing aid to give mouth-to-mouth resuscitation when the inhaled material is toxic, infectious or

corrosive. Seek medical attention.

If swallowed, do not induce vomiting unless directed to do so by medical personnel. Never give anything by mouth to an

unconscious person. Loosen tight clothing such as a collar, tie, belt or waistband. Get medical attention immediately.

Serious Ingestion: Not available.

Section 5: Fire and Explosion Data

Auto-Ignition Temperature: Not applicable.

Flash Points: Not applicable.

Flammable Limits: Not applicable.

Products of Combustion: Not available.

Fire Hazards in Presence of Various Substances: Not applicable.

Explosion Hazards in Presence of Various Substances: Non-explosive in presence of open flames and sparks, of shocks.

Fire Fighting Media and Instructions: Not applicable.

Special Remarks on Fire Hazards: Non combustible

Special Remarks on Explosion Hazards: Not available.

Section 6: Accidental Release Measures

p. 3

Small Spill:

Dilute with water and mop up, or absorb with an inert dry material and place in an appropriate waste disposal container.

Large Spill:

Corrosive liquid. Poisonous liquid. Stop leak if without risk. Absorb with DRY earth, sand or other non-combustible material.

Do not get water inside container. Do not touch spilled material. Use water spray curtain to divert vapor drift. Use water spray

to reduce vapors. Prevent entry into sewers, basements or confined areas; dike if needed. Call for assistance on disposal. Be

careful that the product is not present at a concentration level above TLV. Check TLV on the MSDS and with local authorities.

Section 7: Handling and Storage

Keep locked up.. Keep container dry. Do not ingest. Do not breathe gas/fumes/ vapor/spray. Never add water to this product.

In case of insufficient ventilation, wear suitable respiratory equipment. If ingested, seek medical advice immediately and show

the container or the label. Avoid contact with skin and eyes. Keep away from incompatibles such as oxidizing agents, organic

materials, metals, alkalis, moisture.

Storage: Keep container tightly closed. Keep container in a cool, well-ventilated area. Do not store above 24°C (75.2°F).

Section 8: Exposure Controls/Personal Protection

Provide exhaust ventilation or other engineering controls to keep the airborne concentrations of vapors below their respective

threshold limit value. Ensure that eyewash stations and safety showers are proximal to the work-station location.

Personal Protection:

Face shield. Full suit. Vapor respirator. Be sure to use an approved/certified respirator or equivalent. Gloves. Boots.

Personal Protection in Case of a Large Spill:

inhalation of the product. Suggested protective clothing might not be sufficient; consult a specialist BEFORE handling this

product.

Exposure Limits:

Hydrogen chloride STEL: 7.5 (mg/m3) from ACGIH (TLV) [United States] STEL: 5 (ppm) from ACGIH (TLV) [United States]

CEIL: 5 (ppm) from NIOSH CEIL: 7.5 (mg/m3) from NIOSH CEIL: 5 (ppm) from OSHA (PEL) [United States] CEIL: 7 (mg/m3)

from OSHA (PEL) [United States]Consult local authorities for acceptable exposure limits.

Section 9: Physical and Chemical Properties

Odor: Not available.

Taste: Not available.

Molecular Weight: Not applicable.

Color: Not available.

pH (1% soln/water): Neutral.

Boiling Point: The lowest known value is 100°C (212°F) (Water).

Melting Point: Not available.

Critical Temperature: Not available.

Specific Gravity: Weighted average: 1.01 (Water = 1) p. 4

Vapor Pressure: The highest known value is 2.3 kPa (@ 20°C) (Water).

Vapor Density: The highest known value is 0.62 (Air = 1) (Water).

Volatility: Not available.

Odor Threshold: Not available.

Water/Oil Dist. Coeff.: Not available.

Ionicity (in Water): Not available.

Dispersion Properties: See solubility in water, diethyl ether, acetone.

Solubility:

Easily soluble in cold water, hot water. Soluble in diethyl ether, acetone.

Section 10: Stability and Reactivity Data

Instability Temperature: Not available.

Conditions of Instability: Incompatible Materials

Incompatibility with various substances: Reactive with oxidizing agents, organic materials, metals, alkalis.

Corrosivity:

Highly corrosive in presence of aluminum, of copper, of stainless steel(304), of stainless steel(316). Non-corrosive in presence

of glass.

Special Remarks on Reactivity:

It reacts with oxidizers releasing chlorine gas. Incompatible with alkalis, amines, metals [copper and alloys (brass), zinc

(galvanized materials), hydroxides, organic materials, alkali metals, carbides, borides, metal oxides, vinyl acetate, acetylides,

sulphides, phospohides, cyanides, carbonates, It can react with formaldehyde. Reacts with most metals to produce flammable

Hydrogen gas.

Special Remarks on Corrosivity:

Highly corrosive. There is no data on corrosivity in presence of zinc, steel, copper or brass. However, hydrochloric acid is

incompatible with copper and copper alloys. It attacks nearly all metals (mercury, gold, platinium, tantalum, silver, and certain

Polymerization: Will not occur.

Section 11: Toxicological Information

Routes of Entry: Absorbed through skin. Dermal contact. Eye contact. Inhalation.

Toxicity to Animals: Acute oral toxicity (LD50): 766 mg/kg [Rat]. (Cobalt chloride hexahydrate).

Chronic Effects on Humans:

CARCINOGENIC EFFECTS: Classified 3 (Not classifiable for human.) by IARC [Hydrogen chloride]. MUTAGENIC EFFECTS:

Mutagenic for mammalian somatic cells. [Cobalt chloride hexahydrate]. Mutagenic for bacteria and/or yeast. [Cobalt chloride

hexahydrate]. DEVELOPMENTAL TOXICITY: Classified Reproductive system/toxin/male [POSSIBLE] [Cobalt chloride

hexahydrate]. May cause damage to the following organs: upper respiratory tract, skin, eyes, teeth.

Other Toxic Effects on Humans:

Very hazardous in case of skin contact (irritant), of ingestion, . Hazardous in case of skin contact (corrosive, sensitizer,

permeator), of eye contact (corrosive), of inhalation (lung sensitizer, lung corrosive).

Special Remarks on Toxicity to Animals: Not available.

Special Remarks on Chronic Effects on Humans:

May cause adverse reproductive effects. May affect genetic material. p. 5

Special Remarks on other Toxic Effects on Humans:

Acute Potential Health Effects: Skin: Causes severe skin irritation and burns. May be absorbed through skin in harmful

amounts. Eyes: Causes severe eye irritation and burns. May cause irritation of the conjuctiva or blindness Inhalation: Causes

irritation and possible burns of the respiratory tract and mucous membranes. May affect the liver and sense organs Ingestion:

May be harmful if swallowed. Causes irritation with vomiting, nausea, diarrhea, pain. May cause burning of the gastrointestinal

tract. Can cause nausea and vomitting. May affect behavior, the cardiovascular system, and urinary system

Section 12: Ecological Information

BOD5 and COD: Not available.

Products of Biodegradation:

Possibly hazardous short term degradation products are not likely. However, long term degradation products may arise.

Toxicity of the Products of Biodegradation: The products of degradation are less toxic than the product itself.

Special Remarks on the Products of Biodegradation: Not available.

Section 13: Disposal Considerations

Waste must be disposed of in accordance with federal, state and local environmental control regulations.

Section 14: Transport Information

Identification: : Hydrochloric Acid Solution UNNA: 1789 PG: III

Special Provisions for Transport: Not available.

Section 15: Other Regulatory Information

Connecticut hazardous material survey.: Hydrochloric acid Illinois toxic substances disclosure to employee act: Hydrochloric

acid Illinois chemical safety act: Hydrochloric acid New York release reporting list: Hydrochloric acid Rhode Island RTK

RTK: Hydrochloric acid Massachusetts spill list: Hydrochloric acid New Jersey: Hydrochloric acid New Jersey spill list:

Hydrochloric acid Louisiana RTK reporting list: Hydrochloric acid Louisiana spill reporting: Hydrochloric acid TSCA 8(b)

inventory: Water; Hydrochloric acid; Cobalt chloride hexahydrate TSCA 4(a) proposed test rules: Hydrochloric acid SARA

302/304/311/312 extremely hazardous substances: Hydrochloric acid SARA 313 toxic chemical notification and release

reporting: Hydrochloric acid 9.8% CERCLA: Hazardous substances.: Hydrochloric acid: 5000 lbs. (2268 kg);

Other Regulations: OSHA: Hazardous by definition of Hazard Communication Standard (29 CFR 1910.1200).

Other Classifications: WHMIS (Canada):

CLASS D-1A: Material causing immediate and serious toxic effects (VERY TOXIC). CLASS D-2A: Material causing other toxic

effects (VERY TOXIC). CLASS E: Corrosive liquid.

DSCL (EEC):

R20- Harmful by inhalation. R25- Toxic if swallowed. R34- Causes burns. R42/43- May cause sensitization by inhalation and

skin contact. S1/2- Keep locked up and out of the reach of children. S23- Do not breathe gas/fumes/vapour/spray [***] S24-

Avoid contact with skin. S36/37/39- Wear suitable protective clothing, gloves and eye/face protection. S45- In case of accident

p. 6

or if you feel unwell, seek medical advice immediately (show the label where possible). S46- If swallowed, seek medical advice

immediately and show this container or label.

HMIS (U.S.A.): Health Hazard: 3

Fire Hazard: 0

Reactivity: 0

Personal Protection:

National Fire Protection Association (U.S.A.): Health: 2

Flammability: 0

Reactivity: 0

Specific hazard: Protective Equipment:

Gloves. Full suit. Vapor respirator. Be sure to use an approved/certified respirator or equivalent. Wear appropriate respirator

when ventilation is inadequate. Face shield.

Section 16: Other Information

Other Special Considerations: Not available.

Created: 10/10/2005 12:59 AM

Last Updated: 05/21/2013 12:00 PM

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Presentation notes:

-Coordination complexes are molecules in which multiple species with lone pairs are bonded to a central cation.

-These are a specific type of bond called a “coordinate bond” where both electrons of the lone pair are donated to the central cation.

-Coordination complexes demonstrate bold and vibrant colors. This is due to a phenomenon known as band splitting.

-Because they are repelled by the ligands, different d-orbitals are repelled more or less intensely by the ligands. Which d-orbitals these are depends on the configuration of the ligands.

-The degree of band splitting, which corresponds to the wavelength the coordination complex absorbs, increases with the strength of interaction of the ligands and the central cation, which increases with the strength of the ligands and the charge and zeff of the central cation.

-Coordination complexes can have multiple shapes; the nature of the band gaps depends on the shape of the complex.

-There are multiple types of coordination complexes. Two of these types are chelates and sandwich compounds. Sandwich compounds are complexes where an aromatic ring acts as a ligand. Chelates are complexes where one molecule acts as multiple ligands.

References

Myers, J. (n.d.). Transition metal complexes and color. Retrieved from http://www.wou.edu/las/physci/ch462/tmcolors.htm

Wang, D. (n.d.). Colors of coordination complexes. Retrieved from

http://chemwiki.ucdavis.edu/Inorganic_Chemistry/Crystal_Field_Theory/Colors_of_Coordination_Compl exes

Volicer, B., & Tello, S. (1998). D-metal complexes. Retrieved from http://faculty.uml.edu/ndeluca/84.334/topics/topic6.htm

Bodner Group. (1998). Coordination complexes and ligands. Retrieved from http://chemed.chem.purdue.edu/genchem/topicreview/bp/ch12/complex.php

Bjerrum, J., McReynolds, J. P., Oppegard, A. L. and Parry, R. W. (2007) Hexamminecobalt(III) Salts, in Inorganic Syntheses, Volume 2 (ed W. C. Fernelius), John Wiley & Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/9780470132333.ch69

Dartmouth College. (1997). Coordination chemistry lab 1. Retrieved from http://www.dartmouth.edu/~chemlab/chem6/cobalt1/full_text/chemistry.html

McClure, M. (n.d.). Preparation of cobalt complexes. Retrieved from http://www.uncp.edu/home/mcclurem/courses/chm226/Cobalt_Complexes.pdf

Lancashire, R. (1995, 01). Werner complexes. Retrieved from http://wwwchem.uwimona.edu.jm/lab_manuals/Werner.html

Brown, T., LeMay, E., Bursten, B., & Murphy, C. (2009).Chemistry: The central science.. (11th ed.). Upper Saddle River, NJ: Pearson Education, Inc.

Lancashire, R. (2002, 7). Cobalt chemistry. Retrieved from http://wwwchem.uwimona.edu.jm/courses/cobalt.html