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Ethers, epoxides and acetals

Diethyl squarate

Also known as Squaric acid diethyl ester, Diethoxycyclobutenedione, 3,4-Diethoxy-3-cyclobutene-1,2-dione

CAS 5231-87-8Formula C8H10O4Molar mass 170.16 g/molEC 629-595-0
GHS signal word: Danger. Pictograms: Acute toxicity (severe), Harmful or irritant, Serious health hazard 10 suppliers listed
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Diethyl squarate chemical structure, C8H10O4, CAS 5231-87-8
2D chemical structure

Key facts

What buyers check first

All properties
CAS number
5231-87-8
Formula
C8H10O4
Molar mass
170.16 g/mol
EC number
629-595-0
HS code
290930
Category
Ethers, epoxides and acetals

What is Diethyl squarate?

Plain description, key identifiers and synonyms

Diethyl squarate is a chemical substance with the molecular formula C8H10O4 and a molar mass of 170.16 g/mol. Its CAS registry number is 5231-87-8. The IUPAC name is 3,4-diethoxycyclobut-3-ene-1,2-dione.

Identifiers

Registry numbers, names and line notations, tap to copy

IUPAC name
3,4-diethoxycyclobut-3-ene-1,2-dione
CAS number
5231-87-8 CAS number cross-checked
EC number
629-595-0
Molecular formula
C8H10O4
MDL number
MFCD00001333
InChIKey
DFSFLZCLKYZYRD-UHFFFAOYSA-N
InChI
InChI=1S/C8H10O4/c1-3-11-7-5(9)6(10)8(7)12-4-2/h3-4H2,1-2H3
SMILES (canonical and isomeric)
CCOC1=C(C(=O)C1=O)OCC

Synonyms

  • Squaric acid diethyl ester
  • Diethoxycyclobutenedione
  • 3,4-Diethoxy-3-cyclobutene-1,2-dione
  • 3,4-diethoxycyclobut-3-ene-1,2-dione
  • 3-Cyclobutene-1,2-dione, 3,4-diethoxy-
  • diethoxycyclobut-3-ene-1,2-dione
  • 1,2-diethoxycyclobutenedione
  • 3,4-Diethoxy-cyclobut-3-ene-1,2-dione
  • Dfsflzclkyzyrd-uhfffaoysa-
  • 1,2-diethoxycyclobutene-3,4-dione
  • 34-Diethoxy-3-cyclobutene-12-dione
  • 3,4-diethoxy-3-cyclobuten-1,2-dion
  • 3,4-diethoxy-3-cyclobuten-1,2-dione
  • 3,4-diethoxy-3 cyclobutene-1,2-dione
  • 3.4-diethoxy-3-cyclobutene-1,2-dione
  • 3,4-diethyoxy-3-cyclobutene-1,2-dione
  • 3,4,-diethoxy-3-cyclobutene-1,2-dione
  • 3,4-Diethoxy-3-cyclobutene-1,2-dione, 98%
  • Diethyl squarate, 3,4-Diethoxycyclobut-3-ene-1,2-dione, 3:4-diethoxycyclobut-3-ene-1:2-dione

Physical and chemical properties

Measured values and descriptors computed from the structure

Physical and chemical properties

Measured values, check the supplier specification for your grade

No measured properties are recorded for this substance yet. Ask suppliers for a technical data sheet.

Values vary by grade. Ask suppliers for the COA or TDS of the batch you buy.

Computed descriptors

Calculated from the structure, useful for screening and formulation

Molecular weight
170.16 g/molcalc.
Exact mass
170.0579 Dacalc.
LogP (octanol/water)
0.08calc.
Topological polar surface area
52.6 Ųcalc.
Hydrogen bond donors
0calc.
Hydrogen bond acceptors
4calc.
Rotatable bonds
4calc.
Heavy atoms
12calc.
Rings
1calc.
Aromatic rings
1calc.
Fraction sp3 carbons
0.5calc.
Formal charge
0calc.
Stereocentres
0calc.
Lipinski rule of five
Passes (0 violations)calc.

Calculated for screening. Confirm critical figures with the supplier.

Murcko scaffold

The ring system that remains when every side chain is removed

Murcko scaffold of this chemical, O=c1ccc1=O

O=c1ccc1=O

1 ring, 6 atoms, the 3-Cyclobutene-1,2-dione ring system.

158 other chemicals share this scaffold

Safety and hazards

GHS classification summary, not a safety data sheet

GHS signal word
Danger
GHS06: Acute toxicity (severe)
Acute toxicity (severe)
GHS07: Harmful or irritant
Harmful or irritant
GHS08: Serious health hazard
Serious health hazard

Hazard statements

  • H301Toxic if swallowed.
  • H312Harmful in contact with skin.
  • H315Causes skin irritation.
  • H317May cause an allergic skin reaction.
  • H319Causes serious eye irritation.
  • H334May cause allergy or asthma symptoms or breathing difficulties if inhaled.
  • H335May cause respiratory irritation.
Precautionary statements (27)
  • P233Keep container tightly closed.
  • P260Do not breathe dust, fume, gas, mist, vapours or spray.
  • P261Avoid breathing dust, fume, gas, mist, vapours or spray.
  • P264Wash skin thoroughly after handling.
  • P264 + P265Wash skin thoroughly after handling. Do not touch eyes.
  • P270Do not eat, drink or smoke when using this product.
  • P271Use only outdoors or in a well-ventilated area.
  • P272Contaminated work clothing should not be allowed out of the workplace.
  • P280Wear protective gloves, protective clothing, eye protection and face protection.
  • P284In case of inadequate ventilation wear respiratory protection.
  • P301 + P316If swallowed: Get emergency medical help immediately.
  • P302 + P352If on skin: Wash with plenty of water.
  • P304 + P340If inhaled: Remove person to fresh air and keep comfortable for breathing.
  • P305 + P351 + P338If in eyes: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing.
  • P317Get medical help.
  • P319Get medical help if you feel unwell.
  • P321Specific treatment (see supplemental first aid instructions on the label).
  • P330Rinse mouth.
  • P332 + P317If skin irritation occurs: Get medical help.
  • P333 + P317If skin irritation or rash occurs: Get medical help.
  • P337 + P317If eye irritation persists: Get medical help.
  • P342 + P316If experiencing respiratory symptoms: Get emergency medical help immediately.
  • P362 + P364Take off contaminated clothing. And wash it before reuse.
  • P403Store in a well-ventilated place.
  • P403 + P233Store in a well-ventilated place. Keep container tightly closed.
  • P405Store locked up.
  • P501Dispose of contents and container in accordance with local regulations.

GHS classification summary, not a safety data sheet (SDS). Classifications can differ by supplier, grade and concentration. Always check the supplier's SDS.

Full safety data and first aid

Diethyl squarate suppliers

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Where suppliers are based

10 suppliers in 3 countries

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Diethyl squarate price

Indicative price range per kg from live supplier offers

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Uses and applications

What the substance is used for, by industry and function

Regulatory status

Inventories, regulations and trade controls that list this substance

No regulatory list memberships are recorded for this substance yet. Always check the rules of the importing and exporting country before trade.

HS code and trade data

Customs classification and reported world trade statistics

Global trade

World import and export statistics for the HS code Diethyl squarate is traded under.

HS 2909.30Indicative HS code

Aromatic ethers and their halogenated, sulphonated, nitrated or nitrosated derivatives

World exports in 2024
$470M
−2.2% vs 2023, imports $432M
2019 to 2024
Top exporters
  1. China45.7%
  2. Germany15.7%
  3. India * partner reported9.9%
Top importers
  1. United States14.3%
  2. China11.8%
  3. India * partner reported8.3%

* Partner reported figures, a lower bound.

Reported customs values in USD, not prices.Full trade data

The HS code shown for Diethyl squarate is indicative (it was assigned by structure rules). Confirm the classification with your customs broker before shipping.

Frequently asked questions

Quick answers about Diethyl squarate, based on the data on this page

What is Diethyl squarate?

Diethyl squarate is a chemical substance with the molecular formula C8H10O4 and a molar mass of 170.16 g/mol. Its CAS registry number is 5231-87-8. The IUPAC name is 3,4-diethoxycyclobut-3-ene-1,2-dione.

What is the CAS number of Diethyl squarate?

The CAS registry number of Diethyl squarate is 5231-87-8.

What is the molecular formula and weight of Diethyl squarate?

The molecular formula of Diethyl squarate is C8H10O4 and its molar mass is 170.16 g/mol.

What is Diethyl squarate used for?

Known uses and roles of Diethyl squarate include building blocks in research and laboratory and screening compounds in research and laboratory.

Is Diethyl squarate hazardous?

Diethyl squarate carries the GHS signal word "Danger". Main hazards: toxic if swallowed, harmful in contact with skin, causes skin irritation. This summary is not an SDS, always read the supplier safety data sheet.

What is the HS code of Diethyl squarate?

Diethyl squarate is usually classified under HS code 290930 (Aromatic ethers and their halogenated, sulphonated, nitrated or nitrosated derivatives). This is indicative, confirm it with your customs broker before shipping.

Where can I buy Diethyl squarate?

CompoundList lists 10 suppliers of Diethyl squarate in United States, China and Japan. Send one free request to get and compare quotes. Your contact details stay private until you accept a quote.

What is the price of Diethyl squarate?

Suppliers quote Diethyl squarate on request because prices depend on grade, purity, quantity and destination. A free request on CompoundList gets you several quotes to compare.

Guides for buyers

Practical guides that help when you source, ship or handle Diethyl squarate

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Data last updated 7 Oct 2026. Details may have changed, please confirm them with the supplier. Report an error on this page
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