Formaldehyde Properties (25 Facts You Should Know)

Formaldehyde is an organic compound made up of carbon, hydrogen and oxygen. Let us discuss about various types of formaldehyde in this article.

Formaldehyde is found to be the simplest organic compound with a functional group of aldehyde. In formaldehyde the carbon oxygen bond is found to be double bond and polar. Formaldehyde is soluble in water ethanol and ether. It’s shape is trigonal planar.

Formaldehyde is found to be a flammable gas which reacts with many substance and polymerise to form various products. Latest discuss about the oxidation state, melting point, boiling point of formaldehyde in the following sections.

Formaldehyde IUPAC name

The IUPAC name of formaldehyde is methanal. It can be also called in other names like methyl aldehyde, formal, methylene oxide and carbonyl hydride.

Formaldehyde chemical formula

The chemical formula of formaldehyde is HCHO.

formaldehyde properties
Structure of Formaldehyde

Formaldehyde CAS number

CAS number of formaldehyde is 50-00-0.

Formaldehyde chemspider ID

The chemspider ID of formaldehyde is 692.

Formaldehyde chemical classification

  • Formaldehyde is the simplest aldehyde where hydrogen atom is attached to aldehydic group.
  • The carbon atom in formaldehyde is sp2 hybridised.
  • It is an organic compound.

Formaldehyde molar mass

The molar mass of formaldehyde is 30.026 gram / mol.

Formaldehyde colour

Formaldehyde is found to be a colourless gas.

Formaldehyde viscosity

The viscosity of aqueous solution of formaldehyde range from 2.083 to 2.835 mPa s at temperature 20 degree Celsius.

Formaldehyde molar density

The molar density of formaldehyde is 0.8153 grams/centimetre cube at temperature – 20 degree Celsius.

Formaldehyde melting point

The melting point of formaldehyde is – 92 degree Celsius or 181 Kelvin. It can be negative 134 degree Fahrenheit.

Formaldehyde boiling points

The boiling point of formaldehyde is -19 degree Celsius or 254 Kelvin it can be – 2 degree fahrenheit.

Formaldehyde state at a room temperature

Formaldehyde is found to be a colourless gas at room temperature.

Formaldehyde ionic or covalent bond

The Bonds present in formaldehyde is covalent bond. There is double bond and two single bonds in formaldehyde. All these bonds are made by the mutual sharing of electrons between the atoms.

Formaldehyde ionic or covalent radius

The bond length of single bond between carbon and hydrogen is 1.11 A0 and the Bond length of double bond between carbon and oxygen is 1.22 A0 .

Formaldehyde electronic configuration

Electronic configuration is the arrangement of electrons in orbital in accordance with aufbau principle. Let us discuss about the electronic configuration of atoms in formaldehyde.

The electronic configuration of carbon is 1s2 2s2 2p2, hydrogen is 1s1, and oxygen is 1s2 2s2 2p4.

Formaldehyde oxidation State

The oxidation state of formaldehyde is found to be zero.

Formaldehyde acidity or alkaline

Formaldehyde is found to be weak acid but a good base. The pka value of formaldehyde is 13.27 when the pka value is high lower will be its acidity. Here formaldehyde has a higher pka value so its acidity will be very low. Also the lone pairs present in oxygen enable it as a good base.

Is formaldehyde odourless?

Formaldehyde is a gas with a pungent suffocating smell.

Is formaldehyde paramagnetic?

Paramagnetic substance will have odd unpaired electrons electrons with spin. Let us study weather formaldehyde is paramagnetic or not.

Formaldehyde is found to be a diamagnetic substance. The central atom present here is carbon which has all paired electrons. Also the lawn pairs present in oxygen is also paired. Therefore formaldehyde is found to be diamagnetic substance.

Formaldehyde hydrates

One of the hydrate formed by formaldehyde is formaldehyde monohydrate with formula its HCHO. H2 O. it is also called methylene glycol or methane diol.

Formaldehyde crystal structure

The crystal structure of formaldehyde is found out through 15k by neutron powder method. According to this method the space group of formaldehyde is P421 C, D4 2d with 8 molecules present per unit cell. These are arranged in a four member squares with a very strong carbon oxygen Bond.

Formaldehyde polarity and conductivity

Formaldehyde is found to be a polar compound with the dipole moment value of 2.330 D. In the carbonyl bond the Oxygen will attract the electrons towards it to create a positive charge on carbon and a negative charge on Oxygen.

The conductivity of formaldehyde nanocomposites were discovered recently.

Formaldehyde reaction with acid

Formaldehyde reacts with amino acids and undergo acid catalyzed cannizaro reaction. It also reacts with HNO3 to form NO2 , carbondioxide and hydrogen gas.

2HCHO + 2HNO3 → 2NO2 + 2CO2 + 3H2

Formaldehyde reaction with base

Formaldehyde react with the base like sodium hydroxide to form methanol and sodium formate. It is also observed that formaldehyde react with the base like Ammonia to form water and formamidine.


6HCHO + 4NH3 → (CH2)6N4 + 6H2O

Formaldehyde reaction with oxide

There is no reaction of formaldehyde with oxide is found. But formaldehyde undergo oxidation to form acids.

Formaldehyde reaction with metal

When formaldehyde reacts with the metals the metals will corrode. Metals and certain metal alloys are found to be sensitive to 1200 ppb of formaldehyde.


Formaldehyde is an organic compound which is used in agriculture, as medicine disinfectant and fungicide. It is also used for the production of urea formaldehyde resins.

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