Experiments with first row transition metals and their compounds

 

  element required compound link to experiment
 

Co

CoCl26H2O

Preparation of anhydrous cobalt(II) chloride. Careful heating of hydrated cobalt chloride produces the anhydrous compound.

*

Co, Hg

HCl (30%)

HgCl2

NH4SCN

any water soluble cobalt(II) salt

Colorful and really remarkable chemistry. In this experiment some amazing color changes can be observed. A beautiful bright red solution is prepared from which slowly very bright blue crystals are precipitated. Beautiful contrasts are produced in this experiment.

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Cr

Cr (pure metal)

HCl (30%)

Divalent chromium, extreme sensitivity to aerial oxidation. Chromium metal is dissolves in conc. hydrochloric acid with exclusion of air, and then it is shown how easily the resulting chromium(II) species are oxidized.

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Cr

K2Cr2O7

(NH4)2Cr2O7

HNO3 (concentrated)

P (red)

Na2SO3

Synthesis and properties of polychromates. Trichromates are produced by recrystallization from conc. nitric acid. Some properties, including a spectacular decomposition reaction, are shown.

 

Cr

K2Cr2O7

Cr2(SO4)312H2O

Anhydrous chromium(III) sulfate from concentrated sulphuric acid? Concentrated sulphuric acid, with dissolved chromium compounds, is heated and a precipitate is formed.

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Cr

K2Cr2O7

H2SO4 (dilute)

HCl (dilute)

HNO3 (dilute)

CH3CH2OH

K2S2O5 (or subst.)

Reduction of dichromate - different colors of reaction product due to complex formation. Dichromate is reduced. The color of the resulting chromium(III) depends on the reductor used, and the anions, present in that solution.

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Cr

(NH4)2CrO4

Nice dendritic crystal structures. Ammonium chromate is dissolved and the solution is allowed to evaporate to dryness.

 

Cr

K3CrO8

Explosive properties of peroxo chromates. A synthesis method for this chemical is given, and its explosive properties are shown.

 

Cr

K2Cr2O7

H2O2

any mineral acid

Beautiful effects with potassium dichromate and hydrogen peroxide. Potassium dichromate crystals are sprinkled on a highly diluted acidic hydrogen peroxide solution. The effect is stunning.

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Cr

K2Cr2O7

NaF

NaCl

H2SO4 (concentrated)

H2O2

Fun with volatile chromium - chromyl chloride . A really beautiful experiment with chromyl chloride vapor, which is poured on a very dilute acidic hydrogen peroxide solution.

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Cr

K2Cr2O7

NaF

NaCl

H2SO4 (concentrated)

Na2SO3

Volatile compounds of chromium - another colored gas . Preparation of chromyl fluoride and chromyl chloride.

*

Cr

H2O2

K2Cr2O7

KOH

Synthesis of potassium tetraperoxo chromate(V) . A detailed description (recipe) for making the energetic compound K3CrO8.

*

Cr

H2O2

(NH4)2CrO4

NH3 (25%)

Synthesis of triammine diperoxo chromium(IV). This is a description of how to make another very energetic chromium peroxo compound. Also some properties of the prepared compound are shown.

*

Cr

K2Cr2O7

HCl (≥ 25%, high purity reagent)

 

Na2SO3

HCl (dilute, hardware store)

Synthesis of potassium chlorochromate(VI). The compound potassium chlorochromate(VI) can easily be prepared. In this webpage it is demonstrated how this can be done with acceptable yield. The resulting chemical compound can be kept indefinitely and may be interesting for further experiments.

* Cr

H2O2

Na2Cr2O72H2O

C5H5N (pyridine)

Na2SO3

H2SO4

Chromium peroxo pyridine complex and its properties. A dark blue insoluble peroxo complex of chromium is made, and some further experiments are performed with this compound. This experiments shows some remarkable color combinations and the peroxo complex is remarkably stable under reducing conditions.
*

Cr

K3CrO8

P (red)

Al (powder)

Explosive mix with red phosphorus and a peroxo chromate . A remarkably powerful and sensitive explosive mix is obtained by mixing potassium tetraperoxochromate(V) and red P.

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Cr

KCr(SO)412H2O

NH3 (5% and 12%)

HCl (10%)

NaOH

Chromium(III) coordination chemistry. This is a simple experiment which shows that by simple boiling an aqueous solution of chromium(III) ions forms a complex with anions present in solution by means of ligand exchange. The experiment demonstrates this effect with sulfate anions, but the effect also exists for many other anions. The ligand exchange is accompanied with a strong change of color.

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Cu

CuSO45H2O

NH3 (5%)

NaOH

Na2SO3

C6H8O5Na (sodium L-ascorbate)

Na2S2O42H2O

Copper redox and coordination chemistry. A series of experiments in which redox and coordination properties of copper are shown. Copper has a very rich aqueous chemistry and this set of experiments shows some of this rich chemistry.

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Cu

Al (foil)

NaCl

CuSO45H2O

HCl (10%)

Influence of combination of copper ions and chloride ions on reactivity of aluminium. A violent reaction only occurs, when both type of ions are present.

 

Cu

CuCl2 (or its hydrate)

Colored flames with metal salts. Metals salts are mixed/dissolved in ethanol, soaked in paper and ignited. One of the salts is copper(II) chloride.

* Cu

CuSO45H2O

KSCN

Na2SO3

HNO3

Complex chemistry of copper in combination with thiocyanate. Copper exhibits an interesting chemistry when it is combined with thiocyanate ion. An intricate interplay of coordination chemistry and redox chemistry leads to many surprising compounds with nice colors.
* Cu

CuSO45H2O

KIO4

KOH

Na2S2O8

Formation of a complex of copper in oxidation state +3. Copper can be oxidized to the +3 oxidation state if it is coordinated to orthoperiodate ions. This complex is stable in aqueous solution, and it has a deep red color, which is very special for copper compounds.
* Cu, S

CuSO45H2O

Na2SO3

Na2S2O5

H2SO3

NaOH

Redox chemistry and coordination chemistry of copper(II) and sulfite at different pH. Sulfite ion and copper(II) ion can react in different ways. Coordination complexes can be formed, but they also can interact in a redox reaction. Quite remarkable compounds can be formed in these reactions. The pH of the solutions has great influence on the actual reactions occurring.
* Cu

CuSO45H2O

HBr (48%)

HCl (30%)

KBr

 

Unexpected colors with copper(II) ions in the presence of halogenide at high concentration. Copper(II) ions form intensely colored red/purple complex ions with bromide at low pH and high concentration.
* Cu

organic

 

CuI

KI

C5H5N

CH3COCH3

A fluorescent compound of copper. This is an experiment, which is not well known. The effect demonstrated in this experiment, however, is striking and it is a shame that so few people know it. A white compound is prepared which exhibits beautiful bright yellow fluorescence under black-light.
* Cu

organic

CuCO3Cu(OH)2

CH3COOH

CH2ClCOOH

CCl3COOH

HCOOH

CH3CH2COOH

CH3C(OH)HCOOH

Inductive effect demonstrated by properties of copper acetate and related complexes. In this experiment, copper acetate, but also several substituted and related compounds are prepared. Their properties are compared and a good explanation can be given by the inductive effect.
* Cu, Cs

CuCl22H2O

CsCl

HCl (30%)

 

CoCl26H2O (optional)

FeCl36H2O (optional)

Red complex of copper and chloride. A really beautiful and remarkable solid chloro complex of copper is produced. The complex has copper in oxidation state +2 and has a bright red color, which is very special for copper in oxidation state +2. A few other similar complexes of other metals are described as well through this webpage.
* Fe

 

FeCl36H2O

FeSO47H2O

NH3

HCl

Preparation of a compound with magnetic properties. Only very mundane chemicals and equipment are needed in this simple, but funny experiment. A precipitate of magnetite is prepared and the precipitate is drawn through a test tube by moving a strong magnet around the test tube.
* Fe

 

K3Fe(CN)6

CH3COOH (white vinegar)

(NH4)3[Fe(C2O4)3]

instead of "ferric ammonium oxalate", "ferric ammonium citrate" can be used as well

Cyanotype, the dawn of photography. One of the oldest processes for making permanent images is demonstrated in this experiment. Using simple chemicals and tools an image (a blue print) is made from flat objects like leaves. The word 'blue print' originally stems from this process.
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Fe, Mn

any soluble Mn salt

any soluble Fe salt

bleach

Oxidizing power of bleach, bringing iron and manganese to highest oxidation state. Simple household bleach is capable of oxidizing iron to its +6 oxidation state and manganese to its +7 oxidation state.

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Mn

KMnO4

C12H22O11 (sugar)

NaOH

Chemical chameleon with permanganate. A dilute solution of potassium permanganate is reduced with an alkaline sugar solution. The solution slowly goes through many colors.

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Mn

KBrO3

CH2(COOH)2

MnSO4xH2O

H2SO4 (dilute)

Oscillating reaction. The classical Bhelousov-Zhabotinsky reaction. A well-known classical, but very beautiful, experiment.

*

Mn

KMnO4

H2SO4(concentrated)

CH3COCH3

High speed image capturing of explosions . A drop of acetone is dripped on a mix of concentrated sulphuric acid and potassium permanganate. The resulting explosion is filmed at 60 frames per second.

*

Mn

KMnO4

H2SO4(concentrated)

CH3COCH3

Liquid from hell -- fire on first contact . This is a spectacular demonstration, very similar to the one above. Acetone, sticking to a glass rod, is put in a mix of conc. sulphuric acid and potassium permanganate.

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Mn

KMnO4

H2SO4(concentrated)

CH3CH2OH

Miniature explosions in a test tube . Potassium permanganate is put in a test tube, containing sulphuric acid, with a layer of ethanol floating on top of the acid. This results in little flashes and crackling noise, after an induction period of a few minutes.

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Mn

KMnO4

NaF

H2SO4 (concentrated)

Na2S2O5 (or Na2SO3)

A volatile compound of manganese and corrosion of glass . A volatile green compound of manganese(VII) is produced from potassium permanganate, sodium fluoride and conc. sulphuric acid.

* Mn

Mn (very pure 99.99%)

MnCl2 (hydrated is OK)

HCl (37%, reagent grade)

KMnO4 (reagent grade)

H2O2 (10% by weight)

Na2SO3

Properties of manganese(II) ion at very high concentration. In this experiment it is shown that manganese(II) ions in aqueous solution are pale pink, also at very high concentration and in the presence of concentrated hydrochloric acid. This is different from what some textbooks claim, which mention the existence of green complexes.
 

Mn

MnO2

Al (powder)

P (red)

Flash powder with manganese dioxide. Manganese dioxide and fine aluminium powder make a powerful flash powder. With red P it can be ignited more easily.

* Ni

NiSO4xH2O

NaOH

KCN

H2SO4 (dilute)

H2O2

ligroin (boiling 40...60 C)

bleach

Nickel in oxidation state +1. In this experiment, nickel is brought to the remarkable oxidation state +1, which is very special for this metal, which usually is in oxidation state +2 in aqueous solutions.
*

Ni

Na2S2O8

HNO3 (dilute) NiSO4xH2O

NaOH

Very high oxidation state of nickel with persulfate. Nickel is brought to +3 or even +4 oxidation state by persulfate ion under alkaline conditions.

*

Ti

Ti (powder, granules)

HCl (30%)

H2O2 (3%)

Na2SO3

Na2S2O8

Aqueous chemistry of titanium. Titanium is dissolved in hydrochloric acid. The resulting purple solution is used as a starting point for exploring the metal's aqueous chemistry.

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V

V2O5

Zn (filings, granules)

NaOH

HCl (dilute)

Na2SO3

Colorful oxidation states of vanadium. Vanadium pentoxide is dissolved in a solution of sodium hydroxide. This solution is acidified and then the vanadium in its +5 oxidation state is reduced, all the way down to +2 oxidation state.

* V

V2O5

KOH

H2O2 (15%)

H2SO4 (dilute)

CH3CH2OH (96%)

P (red)

Isolation of peroxo complex of vanadium. In this experiment a peroxo complex of vanadium is made and this complex is isolated as a dry powdered solid. The isolated compound is stable on storage and has energetic properties. A mix with red phosphorus deflagrates on ignition.
*

V

V2O5

PCl5

Volatile vanadium compound, leading to green gas and red smoke. Phosphorus pentachloride is capable of chlorinating vanadium pentoxide and the resulting compound is volatile and gives rise to formation of interesting green vapor and red smoke when it is heated.

*

Zn, Cu

Zn (granules or sheet)

ZnO

NaOH

Cu (coin)

dilute HNO3 / vinegar

Zinc plating of copper coin. A copper coin is zinc plated by putting it in an alkaline solution, containing zincate ions, while at the same time the coin touches a piece of metallic zinc.

 

 

   

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