CID 3283

C₂H₅OC₂H₅

Diethyl ether

C 4
H 10
O 1

Ball-and-stick Stick Space-filling

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15 atoms, 14 single bonds.

IUPAC name: ethoxyethane
Molar mass: 74.123(11) g/mol
Atoms: 15
SMILES: CCOCC
InChIKey: RTZKZFJDLAIYFH-UHFFFAOYSA-N
PubChem CID: 3283

Made of

C H O

Structural formula of diethyl ether. Each unlabelled corner is a carbon atom, and the four hydrogens on carbon are not drawn. It shows which atoms are joined to which, not the shape. The model above shows the shape.

“Ether” on its own is a loose name for this compound, though the same word also names a whole class of molecules. In Chem1’s account, what makes a molecule an ether is an oxygen atom bonded between two carbon atoms. Here that oxygen joins two ethyl groups, as the formula C₂H₅OC₂H₅ spells out and the IUPAC (International Union of Pure and Applied Chemistry) name ethoxyethane records. The molecular formula, C₄H₁₀O at 74.12 g/mol, is also that of 1-butanol.

At room temperature diethyl ether is a very volatile, colourless liquid, and NIOSH, the US National Institute for Occupational Safety and Health, describes its smell as pungent and sweetish. Its vapour pressure at 25 °C is already 538 mm Hg, and the liquid boils at 34.6 °C. It is made on a large scale by dehydrating ethanol or by adding water to ethylene. Where ethanol itself is produced synthetically, enough ether forms alongside it that no separate synthesis is needed.

Structure and bonding

Diethyl ether’s five heavy atoms run as a zigzag of carbon, carbon, oxygen, carbon, carbon, with the oxygen at the middle bend. Turned edge-on, all five lie in one plane, the fully stretched pose PubChem computed for its model. Ten white hydrogen atoms sit on the carbons: three on each end carbon and two on each carbon beside the oxygen, which carries none. One hydrogen at each end lies in the plane, and the other eight stand in pairs above and below it.

The model’s C–O–C angle measures 111.6° and each C–C–O angle 109.0°, figures of that computed pose. Chem1 describes carbon in most organic compounds as tetrahedrally coordinated, its four bonds pointing to the corners of a tetrahedron, 109.5° apart. Stick drops the spheres and leaves those bends easiest to read.

Space-filling swells every atom to its full size. The hydrogens then crowd around the grey carbons, while the oxygen, with no hydrogen of its own, shows as a red patch in the middle of the chain. Labels prints C, H or O on each atom. All 14 bonds are single, in the model and in the real molecule alike.

Where it turns up

Diethyl ether has been reported in the plants Basella alba, Acca sellowiana and Fragaria, according to the LOTUS natural-products database. Outside nature, the unrefined grade goes into cold-weather starting fluids for diesel and petrol engines, usually mixed with propane, butane and other easily lit, volatile substances. It is used to prime petrol engines as well. The consumer products that contain it are auto products, according to the Consumer Product Information Database.

In laboratories it serves as a solvent and as a reagent in organic synthesis, and the chemical industry runs reactions and extractions in it. It dissolves fats, oils, waxes, gums, alkaloids and perfumes. Makers of photographic film and of pharmaceuticals use it too, and among food additives it is classed as an extraction solvent. Earlier uses in the United States, as a refrigerant, in diesel fuels and in dry cleaning, have lapsed.

Why it matters

Diethyl ether is historically important as an anaesthetic, once breathed in by surgical patients in the United States. That use is now essentially obsolete, because its vapour is flammable or explosive at the concentrations anaesthesia requires, especially in oxygen-enriched mixtures. Other disadvantages count against it as well. The World Health Organization’s drug classification files it among general anaesthetics, as N01AA01.

Breathed in, it passes at once into the blood and quickly on to the brain. How it then causes a reversible loss of consciousness is still unclear. Most theories concern membrane lipids, fat-like molecules, or water-repelling regions of membrane proteins. Some investigators suggest, as a hypothesis, that the target is the GABA (gamma-aminobutyric acid) receptor, a protein channel for ions. Recordings show that ether blocks the sensory pathways to the cortex, the brain’s outer layer.

Only about 8 to 10 per cent of the absorbed ether is metabolised, by a cytochrome P450 enzyme system in the liver, into ethanol and acetaldehyde. Both are rapidly oxidised to acetate. The rest leaves the body unchanged through the lungs.

Properties

Properties of diethyl ether Molar mass summed from IUPAC/CIAAW 2024 standard atomic weights; formula, atom and bond counts and PubChem's molecular weight from PubChem CID 3283.
Property	Value	Unit	Source
Molecular formula (Hill order)	C₄H₁₀O
Molar mass	74.123(11) g/mol	g/mol	IUPAC/CIAAW 2024
Carbon atoms	4
Hydrogen atoms	10
Oxygen atoms	1
Bonds	14
PubChem molecular weight	74.12 g/mol	g/mol	PubChem

Safety

Diethyl ether is an extremely flammable liquid that may cause drowsiness or dizziness and is harmful if swallowed. The International Chemical Safety Card adds that it can act on the central nervous system, leading to narcosis, a drugged stupor, and may cause addiction. The liquid can form explosive peroxides when exposed to air and light, the NIOSH Pocket Guide card for ethyl ether records, and the card lists workplace exposure limits for it. The PubChem Laboratory Chemical Safety Summary gathers the full hazard classification.

Questions

What shape is a diethyl ether molecule?

No single VSEPR (valence shell electron pair repulsion) shape word fits it. The chain C–C–O–C–C has five centres, four carbons and an oxygen, each with bonds of its own, instead of one central atom. Each carbon has four neighbours arranged tetrahedrally, the usual coordination of carbon in organic compounds on Chem1's account. PubChem's computed pose stretches the chain flat, with 111.6° at the oxygen; that angle belongs to the model, not to an experiment.

Does diethyl ether mix with water?

Only to a limited extent. The International Chemical Safety Card puts its solubility at 6.9 g in 100 mL of water at 20 °C, and HSDB (the Hazardous Substances Data Bank) gives 6.04 × 10⁴ mg per litre at 25 °C. Lighter than water and poorly dissolved by it, the liquid ends up floating on top. Most organic solvents, by contrast, mix with it in any proportion.

What is diethyl ether used for?

Mainly as a solvent and as a raw material for chemical syntheses. On the Hazardous Substances Data Bank's figures, in 1974 solvent work took 65 per cent, syntheses 25 per cent and anaesthetic and other medical uses 3 per cent. By 1983 solvents and syntheses together took 75 per cent and engine starting fluids the remaining 25. It is sold in several grades, from unrefined and technical ether to reagent grades and anaesthetic ether.

Why is diethyl ether vapour a fire risk?

The vapour is 2.55 times as dense as air, so it can spread along the ground and be lit by a flame some distance from the liquid. Vapour and air together form explosive mixtures, and the liquid's flash point, −45 °C, lies far below room temperature.

Made of the same elements

C₄H₉OH 1-Butanol 15 atoms, 14 single bonds.
C₄H₈O Butanone 13 atoms, 12 bonds.
C₃H₇OH 1-Propanol 12 atoms, 11 single bonds.
C₃H₇COOH Butyric acid 14 atoms, 13 bonds.
CH₃COOC₂H₅ Ethyl acetate 14 atoms, 13 bonds.
C₃H₈O Isopropyl alcohol 12 atoms, 11 single bonds.
C₃H₈O₂ Propylene glycol 13 atoms, 12 single bonds.
C₃H₆O Acetone 10 atoms, 9 bonds.

All 51 compounds made of carbon, hydrogen and oxygen

C₃H₈O₃ Glycerol 14 atoms, 13 single bonds.
CH₃OCH₃ Dimethyl ether 9 atoms, 8 single bonds.
C₂H₅OH Ethanol 9 atoms, 8 single bonds.
C₆H₅OH Phenol 13 atoms, 13 bonds.
C₂H₅COOH Propionic acid 11 atoms, 10 bonds.
C₆H₅CHO Benzaldehyde 14 atoms, 14 bonds.
C₂H₆O₂ Ethylene glycol 10 atoms, 9 single bonds.
C₃H₆O₃ Lactic acid 12 atoms, 11 bonds.
CH₃CHO Acetaldehyde 7 atoms, 6 bonds.
C₆H₅COOH Benzoic acid 15 atoms, 15 bonds.
C₂H₄O Ethylene oxide 7 atoms, 7 single bonds.
C₄H₆O₅ Malic acid 15 atoms, 14 bonds.
C₈H₈O₃ Methyl salicylate 19 atoms, 19 bonds.
C₈H₈O₃ Vanillin 19 atoms, 19 bonds.
CH₃COOH Acetic acid 8 atoms, 7 bonds.
C₆H₈O₆ Ascorbic acid 20 atoms, 20 bonds.
C₆H₁₂O₆ Fructose 24 atoms, 24 single bonds.
C₆H₁₂O₆ Glucose 24 atoms, 24 single bonds.
CH₃OH Methanol 6 atoms, 5 single bonds.
C₇H₆O₃ Salicylic acid 16 atoms, 16 bonds.
C₄H₆O₆ Tartaric acid 16 atoms, 15 bonds.
C₉H₈O₄ Aspirin 21 atoms, 21 bonds.
C₆H₈O₇ Citric acid 21 atoms, 20 bonds.
C₂H₄O₃ Glycolic acid 9 atoms, 8 bonds.
CH₂O Formaldehyde 4 atoms, 3 bonds.
HCOOH Formic acid 5 atoms, 4 bonds.
H₂CO₃ Carbonic acid 6 atoms, 5 bonds.
H₂C₂O₄ Oxalic acid 8 atoms, 7 bonds.
C₁₀H₂₀O Menthol 31 atoms, 31 single bonds.
C₁₄H₁₄O₃ Naproxen 31 atoms, 32 bonds.
C₁₅H₁₆O₂ Bisphenol A 33 atoms, 34 bonds.
C₁₃H₁₈O₂ Ibuprofen 33 atoms, 33 bonds.
C₂₀H₁₄O₄ Phenolphthalein 38 atoms, 41 bonds.
C₁₈H₂₄O₂ Estradiol 44 atoms, 47 bonds.
C₁₂H₂₂O₁₁ Lactose 45 atoms, 46 single bonds.
C₁₂H₂₂O₁₁ Sucrose 45 atoms, 46 single bonds.
C₁₉H₂₈O₂ Testosterone 49 atoms, 52 bonds.
C₁₆H₃₂O₂ Palmitic acid 50 atoms, 49 bonds.
C₂₁H₃₀O₂ Progesterone 53 atoms, 56 bonds.
C₁₈H₃₄O₂ Oleic acid 54 atoms, 53 bonds.
C₂₁H₃₀O₅ Cortisol 56 atoms, 59 bonds.
C₂₇H₄₄O Cholecalciferol 72 atoms, 74 bonds.
C₂₇H₄₆O Cholesterol 74 atoms, 77 bonds.