Learn the list of ligands, EDTA toThiamethoxam.

School Science Lessons
(UNChemLigand)
2023-09-17b

Ligands, EDTA
Contents
1.0 Ligands
2.0 Reactions of metals with ligands
4.0 EDTA

Paraffin oil
Phenolic compounds by name
Phenyl group
16.1.0 Neonicotinoid insecticides

1.0 Ligands
A ligand can be an ion or an atom that can form a co-ordination complex with a central atom, usually a metal.
A ligand is a molecule that selectively binds to another molecule.
Transition metals (transition elements) can form bonds called dative covalent bonds by accepting pairs of electrons (shown as :), from other ions or molecules.
Both the shared electrons come from the same atom.
The ion or molecule that forms the bond with the transition metal is called a ligand, e.g. :Cl - , :CN - , H2O:, :NH3.
More than one ligand can bind to a transition metal ion to form a complex ion.
The number of ligands so bonded is called the co-ordination number, for example:
co-ordination number 4: [CoCl4] 2- ,
co-ordination number 6: [CO(NH3)6] 3+

Experiments
12.5.9 Chromium ions in solution, (See: 6.)
1.1 Copper (II) sulfate solution with ammonia solution, ligand substitution
1.2 Copper (II) sulfate solution with concentrated hydrochloric acid, ligand substitution

1.1 Copper (II) sulfate solution with ammonia solution, ligand substitution
The copper ion, Cu 2+ (aq), in aqueous solution, forms a blue complex ion, [Cu(OH2)6] 2+ , with 6 water molecules.
The blue complex is the cause of the blue colour of copper sulfate solution.
Ammonia solution contains hydroxide ions, OH - , and is alkaline.
Add ammonia solution drop by drop to the pale blue copper sulfate solution.
A pale blue precipitate of insoluble copper hydroxide forms.
Cu 2+ (aq) + 2OH - (aq) --> Cu(OH)2 (s)
Add more ammonia solution to dissolve the copper hydroxide to form the deep blue complex ion, [Cu(NH3)4(OH2)2] 2+ .
Four of the 6 water molecules in the blue complex ion, [Cu(OH2)6] 2+ have been replaced by ammonia ions, leaving 2 water molecules still there.
So the number of ligands around the copper ion is still 6.

1.2 Copper (II) sulfate solution with concentrated hydrochloric acid, ligand substitution
The copper ion, Cu 2+ (aq), in aqueous solution, forms a blue complex ion, [Cu(OH2)6] 2+ , with 6 water molecules.
The blue complex is the cause of the blue colour of copper sulfate solution.
Concentrated hydrochloric acid has a high concentration of chloride ions, which are better ligands than water,
because they are negatively charged ions and are attracted electronically to the copper ion, Cu 2+ .
Add concentrated hydrochloric acid drop by drop to the pale blue copper sulfate solution.
The solution turn yellow-green as the chloride ion ligands, Cl - , replace water in the complex ion.
Four chloride ions replace the 6 water molecules in the blue complex ion to form the yellow-green [CuCl4] 2- complex ion.
So the number of ligands around the copper ion has dropped from 6 to 4.

2.0 Reactions of metals with ligands
See diagram 16.4.4: EDTA molecule
Metals and ligands form co-ordination bonds (co-ordination complexes), with both electrons coming from the ligand.
Ligands have a lone pair of electrons.
Metals do not have enough electrons to form covalent bonds by sharing one electron from the metal ion with one electron from the bonded atom.
The metals involved include Ag + , Al 3+ , Cu 2+ and Fe 3+ .
Examples of ligands include: -NH3, -OH2, -Cl - , -OCOCH3 - , -EDTA -4 , -NTA -3 .
Complexes include metal carbonyls, metal (CO)4, [Cu(H2O)6] 2+ , [PtCl4] 2- .
Metals usually bond with 4 to 6 ligands.
Chelates are ligands that bind more than one compound.
Copper forms a series of ligands with ammonia:
Cu 2+ + NH3 <--> CuNH3 2+
CuNH3 2+ + NH3 <--> Cu(NH3)2 2+
Cu(NH3)2 2+ + NH3 <--> Cu(NH3)3 2+
Cu(NH3)3 2+ + NH3 <--> Cu(NH3)4 2+
Ammonia is a monodentate (one tooth) ligand, because it forms one co-ordination bond with a metal.
Ethanediamine, (H2NCH2CH2NH2), is a bidentate (two tooth) ligand, because it forms two co-ordination bonds with a metal.
Triethanetetramine (trien) and nitrilotriacetic acid (NTA), are tetradentate ligands, because they form one four co-ordination bonds with a metal.
Ethanediaminetetraacetate (EDTA 4- ), is a hexadentate ligand, because it forms six co-ordination bonds with a metal.

4.0 EDTA
EDTA, C10H16N2O8, Ethylenediaminetetraacetic acid, edetic acid
EDTA, C10H14N2Na2O8.2H2O, Ethylenediaminetetraacetic acid disodium salt, Toxic if ingested
Chelating agent
A chelating agent binds to metals and prevents them from participating in chemical reactions.
Calcium disodium EDTA, C10H12CaN2Na2O8, is an odourless crystalline powder, light salt flavour, food additive, preservative, flavoring agent.
It is used in sauces, canned food products and cosmetic prodyucts to preserves texture, flavor and colour, increase shelf life, enables foaming
It prevents metals accumulating, prevents discoloration and is used to treat metal toxicity, e.g. lead or mercury poisoning.
Eriochrome black T (metal indicator for the titration of calcium and magnesium ions with EDTA)
1,2-diaminoethane, C2H8N2, C2H4(NH2)2, ethylenediamine, smells like ammonia, related to EDTA, Toxic by all routes, corrosive
1,2-diaminoethane, Solution < 1%, Not hazardous
EDTA, Ethylenediaminetetraacetic acid, edetic acid, [(HOOCCH2)2NCH2], C10H16N2O8,
A chelating agent that binds calcium and heavy metal ions including lead, so used to treat lead poisoning, food additive, Anticoagulant, EDTA disodium, C10H14N2Na2O8.2H2O, edetic acid disodium salt.
4.1 EDTA, C10H14N2Na2O8.2H2O, Ethylenediaminetetraacetic acid disodium salt
4.2 Ion exchange resins, deionized water
3.3.7 Prepare nylon polymer:
19.1.22 Sequestrants, food additives Experiments
9.2.4 Mineral deficiency experiment, hydroponics, EDTA
12.4.4 Tests for metal ions, using EDTA
12.4.5 Tests for water hardness, EDTA titration, Calmagite indicator
12.4.6 Tests for water hardness, EDTA titration, Eriochrome Black T indicator

4.1 EDTA
EDTA, ethylene diamine tetra acetic acid (HOOC.CH2)2N(CH2)2N(CH2.COOH)2
See diagram 16.4.4: EDTA molecule
1. Ethylenediaminetetraacetic acid (HOOCCH2)2N(CH2)2N(CH2COOH)2, edathamil, sequestering agent for metal ions, Mg 2+ , Ca 2+ .
Complexing agent for most metal ions, especially Ca 2+ and Mg 2+ .
Used for water softening, remove scale from kettles, medical removal of excess metallic ions.
If a ligand is defined as a small molecule that binds to a larger molecule, then chelates can be said to bring about the complexation of a ligand.
The terms ligand, chelate, chelating agent and sequestering agent are used in slightly different ways in chemistry, medicine, and general industry.
If EDTA = H4Y, then the disodium dihydrate form = Na2H2Y.2H2O
H2Y 2- + Ca 2+ <--> CaY 2- + 2H +
2. EDTA disodium salt, ethylenediaminetetraacetic acid disodium salt dihydrate, C10H14N2Na2O8.2H2O, EDTA disodium salt,
ethylenediaminetetraacetate dihydrate (HOOCCH2)2N(CH2)2N(CH2COONa)2.2H2O, (0.1 M, solution + sodium azide), for electrophoresis, molecular biology.
Electrophoresis, (Commercial)
3. A chelate is a metal ion bound to two or more atoms of a chelating agent (sequestering agent),
For example, the simple chelating agent 1,2-diaminoethane (ethylene diamine), NH2.CH2.CH2.NH2, forms bonds to a metal ion through its nitrogen atoms.
[Diaminoethane, ethylene diamine, C2H4(NH2)2, ligand, chelating agent, Toxic by all routes, Corrosive]
Porphyrin chelates include haeme, in haemoglobin, bonded to iron (II) ion, and chlorophyll bonded to Mg (II) ion.
Similarly vitamin B-12 has cobalt (II) ion bonded to a chelating agent.
4. The synthetic chelating agent EDTA can form complexes with calcium and magnesium ions.
So it can form the calcium complex [Ca(EDTA)] 2- .
The sodium salt used as an antidote for metal poisoning, an anticoagulant, enzyme deactivation, bactericide, industrial processes.
EDTA disodium salt, (HOOC.CH2)2N(CH2)2N(CH2.COO.Na)2.2H2O.
EDTA deactivates the enzymes containing metal ions that cause food spoilage, loss of colour and loss of flavour.
EDTA dissolves the calcium carbonate scale caused by hard water and prevents stored blood from clotting by sequestering calcium ions.
Calcium disodium EDTA is a treatment for lead poisoning by exchanging its chelated calcium for lead so lead chelate is excreted.
5. Industrial synthesis of EDTA
NH2.CH2.CH2.NH2 + 4 H.CHO + 4 Na.CN + 4 H2O
(Na.OOC.CH2)2N(CH2)2N(CH2.COO.Na)2 + 4 NH3
1, 2-diaminoethane (ethylenediamine) + methanal (formaldehyde) + sodium cyanide + water -->
sodium salt + ammonia (Na.OOC.CH2)2N(CH2)
2N(CH2.COO.Na)2 + 4 HCl -->
(HOOC.CH2)2N(CH2)2N(CH2.COOH)2 + 4 NaCl
sodium salt + hydrochloric acid --> EDTA + sodium chloride

4.2 Ion exchange resins, deionized water
Let RZ = the resin, an organic polymer matrix.
Charged groups are bound to the resin.
Cation exchange resin, H + form, to remove cations, e.g. Ca 2+ , from solution.
2RZ-SO3 - H + + Ca 2+ <--> RZSO3 - )2Ca 2+ + 2H +
Anion exchange resin, OH- from, to remove anions, e.g. Cl - , from solution
RZ-N(CH3)3 + OH - + Cl - -->RZ-N(CH3)3 + Cl - + OH -
To "soften" water, usually only a cation exchange resin is used.
If both a cation exchange resin and an anion exchange resin are used with tap water to remove ionic salts by ion exchange, the resulting solution is deionized water,
a cheaper alternative to distilled water.

9.2.4 Mineral deficiency experiment, hydroponics, EDTA
To make four kinds of culture solutions based on large elements, trace elements and iron solution.
Among them, the mother solutions of the iron solution and trace elements may be kept in the refrigerator.
The main elements are compounded in two kinds of reserve solutions (A and B).
The table of the prescription of reserve solution, unit: gram / litre water
Table 9.9.18.5

Solution	Chemical Name	Molecular Formula	Volume g / litre
A, main	calcium nitrate crystals	Ca(NO3)2.4H2O	30
"	potassium nitrate (nitrate of potash)	KNO3	.
B, main	ammonium phosphate (di-ammonium hydrogen phosphate)	(NH4)2 HPO4	25
.	magnesium sulfate (Epsom salts)	MgSO4.7H2O	25
C, iron	EDTA, disodium salt (disodium ethylene diamine)	EDTA-Na2	2.682
.	ferrous sulfate (iron (II) sulfate-7-water)	FeSO4.7H2O	.
D, trace	boric acid (boracic acid)	H3BO3	2.86
.	zinc chloride	ZnCl2	0.22
.	copper (II) sulfate crystals	CuSO4.5H2O	0.08
.	molybdic acid	H2MoO4	0.02
.	manganese chloride	MnCl2	0.08

Dissolve EDTA disodium salt in hot water, then add iron (II) sulfate-7-water and mix while it is hot.
Do not mix the Solutions A and B to avoid precipitating calcium sulfate.
Keep Solutions A and B in a shaded place.
Keep Solutions C and D in the refrigerator.
In Solution A the proportion of calcium nitrate and potassium nitrate can be adjusted depending on the water quantity and the variety of plants at the place in the locality.
For example if hardness of water is great reduce the quantity of calcium nitrate.
Make up the solutions with deionized water and regulate pH to 5.5 to 5.8 with HNO3 or KOH according to the needs of different vegetables, e.g. if the leaf should has the high content of nitrogen increase the content of phosphorus and potassium after the flowering phase.

12.4.4 Tests for metal ions in water, EDTA chelates
The different forms of hardness are expressed as "calcium carbonate hardness".
EDTA is [ethylene diamine tetra-acetic acid, HOOCCH2)2N(CH2)2N(CH2COOH)2].
The disodium salt of EDTA combines with metals to form chelates.
Chelates are compounds where a multidentate ligand, e.g. as an enolate anion of a diketone, is bound to a central atom of a co-ordination complex.
EDTA is a complexone and is used in special soaps to remove metal contamination and as a chelating agent for analytical determination of metal contamination.
It is available as "EDTA (0.5 M)", which is a concentrated volumetric solution for dilution to prepare 1 litre of 0.5 M standard solution.
Experiment
1. Prepare a 0.01 M EDTA solution by dissolving 1.861 g in 500 mL water.
2. Prepare pH 11 buffer solutions by adding 7.0 g ammonium chloride solution to 57 mL of concentrated aqueous ammonia solution.
Dilute to 100 mL.
BE CAREFUL!
3. Prepare an approximate 0.01 M solution MgCl2.6H2O by dissolving 2 g in 1 litre.
4. Eriochrome Black T or Erio T indicator is the indicator for determining Ca 2+ , Mg 2+ and Zn 2+ with EDTA.
Dissolve 0.2 g EDTA powder in aqueous ammonia solution.
Pour 100 mL of the water to be tested in a conical flask on white paper.
Add 1.0 mL of the Mg 2+ solution, 3 drops of "Erio T" indicator solution and 1 mL of the buffer solution.
Add drops of EDTA solution until a blue colour appears.
1 mL EDTA solution / 1.0 mg CaCO3.
Ca 2+ + H2EDTA2 <--> CaEDTA 2- + 2H + .

12.4.5 Tests for water hardness, EDTA titration, Calmagite indicator
The usual form of EDTA used for measuring water hardness is Na2EDTA.2H2O, the ethylenediaminetetraacetic acid disodium dihydrate salt.
In this ion exchange reaction, the EDTA is in the sodium form and only the cation Ca 2+ is removed.
Let RZ = the ion exchange resin.
2RZ-SO3 - Na + + Ca 2+ <--> (RZ-SO3 - )2Ca 2+ + 2Na +
Make the following solution: 5.0 mL of water sample, 1.0 mL of 1.5 M NH3 / 0.3 M NH4Cl buffer, 0.1 mL of 2% ascorbic acid solution, 1.0 mL of 0.01 M Na2MgEDTA / 0.1 M NH3 solution, 3 drops of
0.1% Calmagite indicator.
The buffer keeps the hydrogen ion concentration of the solution at the optimum value.
The ascorbic acid solution prevents oxidation of the indicator.
Titrate the solution with 0.01 M Na2EDTA (Na2EDTA.2H2O) until the colour of the solution changes from red to blue.
Repeat with a blank titration 5.0 mL of deionized water instead of the water sample.
Subtract the volume the blank titration from the volume of the water sample titration.

1. Calculate the water hardness in units of millimoles per litre, i.e. the sum of the calcium and magnesium ion concentrations.
2. Calculate the water hardness in units of parts per million of CaCO3 (ppm, 1 ppm = 1 mg per litre), i.e. milligrams of CaCO3 per litre, assuming that the ions titrated came from CaCO3.
Magnesium usually also occurs in hard water, but this second calculation is often used by water engineers for convenience.
(mg CaCO3 / L) = (mmol Ca 2+ + Mg 2+ / L) × (1 mol CaCO3 / mol Ca 2+ + Mg 2+ ) × (100 g CaCO3 / mol CaCO3).

12.4.6 Tests for water hardness, EDTA titration
Eriochrome, C20H12O7N3Na, solochrome black, toxic if ingested
1. Use Eriochrome Black T indicator and titrate with EDTA.
Check that the pH is 10 when adding the buffer, using a pH meter.
Use Eriochrome black T indicator that has been ground with salt rather than a liquid.
EBT is blue in a buffered solution at pH 10.
It turns red when Ca 2+ ions are added.
At the blue end-point, sufficient EDTA has been added, the metal ions are chelated by EDTA, to leave the free indicator molecule.
Eriochrome Black T, C20H12N3O7SNa, is blue in protonated form, but turns red when forming a complex with Ca 2+ , Mg 2+ , and some other metal ions.
EDTA, Ethylenediaminetetraacetic acid, aminopolycarboxylic acid, [CH2N(CH2CO2H)2]2.
2. Hardness Ratings (mg CaCO3/L equivalent): < 15 very soft; 15-50 soft; 50-100 medium hard; 100-300 hard; > 300 very hard
3. The quantity of hardness ions will be determined by titration.
EDTA, a weak acid, will be used as the titrant.
In its ionized form, it is able to form soluble complexes with calcium and magnesium cations.
The indicator added to the sample is Eriochrome Black T.
Initially, the indicator will form a complex with the cations.
When complexed it is red in colour.
As the EDTA is added dropwise to the sample, it replaces the Erio T and forms more stable complexes with calcium and magnesium.
When the indicator is released by the metal ions, it has a distinct blue colour.
Therefore, the endpoint of the titration is marked by the colour change from red to blue.
To determine the hardness of water by measuring the concentrations of calcium and magnesium in water samples by titration.
The titration should be completed within 5 minutes of buffer addition.
Some metal ions may interfere in the titration by causing fading or indistinct end points.
Experiment
1. Clean a 25 mL volumetric pipette by rinsing it with 10% HCl, then 2 washes of distilled water.
Hold the pipette horizontally and rotate it so that the liquid washes all the inside surfaces.
Place the pipette on a towel.
Label all glassware.
Clean and fill the burette
2. Titrant solution: Pour about 100 mL of 0.01M EDTA titrant solution into a 250 mL beaker
3. Analysis solution: Pipette 25 mL of the water sample into a conical flask and dilute it with 25 mL distilled water.
Add at least one mL of pH 10 buffer solution to the sample.
The pH should be 10, so check the pH with pH paper or a pH meter.
4. Add a 1-2 drops Eriochrome Black T indicator (or a small scoop of powder indicator formulation) to the conical flask.
The solution should now be red / pink.
5. Titration: Test 1. Immediately begin to titrate the sample two drops at a time.
Be careful to titrate slowly near the endpoint, as the colour will take about 5 seconds to develop.
Thus, add the last few drops at 3-5 second intervals.
The endpoint colour is blue.
6. Perform this procedure at least two more times, Test 2 and Test 3.
The titre volumes should be within 0.1 mL of each other.

Titre (mL)	Test 1	Test 2	Test 3
Initial Volume	-	-	-
Final Volume	-	-	-
Titre Volume	-	-	-

Express hardness as parts per million (mg per litre) of equivalent CaCO3.
If the titration required 5 mL EDTA, the calculation is as follows:
(5 mL 0.01 M EDTA / 0.025 L sample) x ( 1 mg equivalent CaCO3 / 1 mL 0.01 M EDTA) = 200 ppm CaCO3
Reference: Standard Methods for the Examination of Water and Wastewater, 20th ed., L. S. Clesceri, A. E. Greenberg, A. D. Eaton
editors, 1998, American Public Health Association.

Paraffin oil
Paraffin oil, Kerosene, Highly flammable, toxic by all routes, avoid vapour inhalation, skin irritant
Use kerosene to clean chrome-plated taps, to soak greasy overalls before washing with soap powder.
Use kerosene-soaked cheesecloth left to dry for furniture dusters.
Paraffin, hard paraffin wax (chunks), alkane mixture, CnH2n+2), paraffin wax black 43 / 46.
The term "paraffins" was the former name for "alkanes".
Paraffin (Latin parum little, affinis connected), because of its low chemical activity.
The name invented by German chemist Karl Reichenbach in 1830.
1. Paraffin, FP 60 o C (UK paraffin oil) (USA, Australia, kerosene), (also kerosine, "kero"), is a petroleum fraction containing a mixture of about ten different hydrocarbons, 10 to 16 carbon atoms per molecule, depending on the origin of the original petroleum.
Kerosene has a flash point about 25 oC, so it is a relatively safe fuel.
Use paraffin oil, kerosene, in a well-ventilated space for kerosene lamps and domestic heaters, but do not use it as a degreaser of engines.
2. Paraffin wax is alkanes C20H42) to C40H82, and is used to make candles, polish, "wax" paper.
3. Liquid paraffin, (petrolatum liquid, paraffin liquid), is a pure mineral white oil emulsion used as a medicine.
It is a colourless, tasteless, liquid form of petroleum jelly, mixture of >C12 alkanes, known as petrolatum jelly ("Vaseline").
White paraffin, is another kind of petroleum jelly.
Paraffin wax, MP. 45 to 65 oC (pastillated wax, 52 oC), relative density 0.9
Paraffin wax, fractional distillation
Kerosene, paraffin oil, distillation
Kerosene, for bath cleaning, Prepare
Temporary emulsions and permanent emulsions
Emulsions
Catalytic cracking of kerosene
Prepare soap

Phenolic compounds, by name
Anethole
Arbutin
Bergenin
Caffeic acid
Capsaicin
Carvacrol
Catechol
Chlorogenic acid
< a href="../topics/topicIndexCarbon.html#CichoricacidH">Cichoric acid
Cinnamaldehyde
Cinnamic acid
Coumaric acid
Coumarin
Cresol
Curcumin
Cyanidin
Emodin
Ethylphenol
Estradiol (oestradiol), C18H24O2
Estragole
Eugenol
Ferulic acid
Furanocoumarins
Gallic acid
Guaiacol, Methyoxyphenol
Juglone
Mangiferin
Methyl salicylate
Myristicin
Nordihydroguaiaretic acid
O-leuropein
Paeonol
Piceatannol
Plumbagin
Quercetin
Raspberry ketone
Resorcinol
Resveratrol Rosmarinic Acid
Salicyclic acid
Sesamol
Shikonin
Shogoal
Silibinin
Sinapinic acid
Tannic acid
Thymol
Tyrosine
Tyrosol
Umbelliferone
Urushiol
Vanillin
Zingerone

Phenyl group, (C6H5)
1-phenylazo-2-naphthol, sudan I, C.I. Solvent Yellow 14, toxic. skin irritant, purchase solution
3-phenylpropenoate, C11H12O2, (Ethyl cinnamate, 3-phenylpropenoate, toxic, Flammable)
3-phenyl propenoic acid, C9H8O2, C9H10O2, C6H5CH:CHCOOH, cinnamic acid, toxic if ingested
Phenyl benzoate, C13H10O2 (recrystallization experiments, ethanol solvent), benzene substitute, toxic, Irritant, Flammable
Phenyl bromide, Bromobenzene: 12.18.3
Phenylalanine, C9H11NO2

Phenylalanine, C9H11NO2
Phenylamine, C6H5NH2
, Phenylethene, (C6H5CH,CH2), vinyl benzene, styrene
Phenylhydrazine, C6H8N2, Highly toxic by all routes
Phenylhydrazine, C6H8N2, Solution / mixture < 1%, Not hazardous
Phenylhydrazine hydrochloride, phenylhydrazinium chloride, Highly toxic by all routes
Phenylthiocarbamide, C7H8N2S, PTC, phenylthiourea, (PTU), tasters: #9.9.2
Phenylthiocarbamide, C7H8N2S, PTC: 1.13
Phenylthiourea, C7H8N2S, phenylthiocarbamide, 1-phenyl-2-thiourea (rat poison), Highly toxic if ingested, asthmatics may be allergic
Phenylthiourea, C7H8N2S, 0.1% solution soaked in paper used for taster / non-taster genetic test, Experiment Not permitted in schools
Phenylurea, C6H5NHCONH2, phenylcarbamate, toxic if ingested

Neonicotinoid insecticides
Neonicotinoid insecticides, neonics, are systemic insecticides, so taken to all parts of the plant, used for seed treatment, pot plant soil treatment, turf spray,
They are used as foliar sprays in glass houses for fruit trees.
They have been blamed for the present decline in the bee population and so have been partially banned in some countries.
Press release: 15/03/2013
The European Food Safety Authority gave the most compelling evidence that toxic chemicals "neonicotinoid pesticides" could be responsible for the bee deaths.
Italy has banned some uses of these bee killing pesticides and has already seen it's bee populations come back,
However, Bayer and Sygenta lobbied to prevent a Euro-wide ban, for fears it would harm their global business.
It seems they're close to having the support of the UK, Spain, and Germany, who want to protect their biggest chemical corporations.
Now the issue is coming to a boil.
Just weeks ago, Avaaz delivered a petition signed by over 2.5 million of us to the European Commission, who proposed a ban day later.
EU parliamentarians stepped up their pressure and several other governments have announced plans to push ahead with new legislation to ban the pesticides.

16.1.0 Neonicotinoid insecticides:

Acetamiprid
Acetamiprid, C10H11ClN4, neonicotinoid insecticide, has population level effects on honeybees by interfering with honeybee reproduction and navigation.

Clothianidin
Clothianidin, C6H8ClN5O2S, neonicotinoid insecticide, is neurotoxic and is highly toxic to bees and other non-target insects.
In 2008 a massive bee die-off occurred in Germany, which was subsequently associated with clothianidin.

Fipronil
Fipronil, C12H4Cl2F6N4OS, neonicotinoid insecticide, is used for indoor and turf pest control.
It causes reduced behavioural function and learning performances in honeybees.

Imidacloprid
Imidacloprid, C9H10ClN5O2, neonicotinoid insecticide, is used in agriculture as foliar and seed treatments, for indoor and outdoor insect control.
It is the most popular neonicotinoid.
It has been found to be highly toxic to bees and other beneficial insects.
It is also toxic to upland game birds, is generally persistent in soils and can leach to groundwater.
It cause disruptions in mobility, navigation, and feeding behaviour.

Thiacloprid
Thiacloprid, C10H9ClN4S, neonicotinoid insecticide, is used to control sucking and biting insects in cotton, rice, vegetables, pome fruit, sugar beet, potatoes and ornamentals.
Low doses are highly toxic to honeybees and fish.

Thiamethoxam
Thiamethoxam, C8H10ClN5O3S, neonicotinoid insecticide, is a systemic insecticide absorbed and transported to all parts of the plant.
If bees eat the pollen, it interferes with nerve cell information exchange, paralysing the insect.