Coordinate Covalent Bonding
A covalent bond is an attractive force that is caused by two electrons being shared between two non-metal atoms. Bonds between non-metals tend to be covalent bonds because they don’t have enough electrons and therefore need to share their electrons. A single covalent bond is when two electrons are shared between two atoms. A double covalent bond is when two pairs of electrons are being shred between two atoms. A triple covalent bond is when three pairs of electrons are being shared between two atoms.
An oxygen gas molecule (O2) exists as a pair of oxygen atoms joined together by a double covalent bond. Two pairs of electrons are shared by the two atoms. These four electrons spin around the atoms holding them together. A coordinate covalent bond is a covalent bond in which both of the shared electrons came from the one atom. Once formed coordinate covalent bonds are identical to ordinary covalent bonds.
An oxygen gas molecule (O2) exists as a pair of oxygen atoms joined together by a double covalent bond. Two pairs of electrons are shared by the two atoms. These four electrons spin around the atoms holding them together. A coordinate covalent bond is a covalent bond in which both of the shared electrons came from the one atom. Once formed coordinate covalent bonds are identical to ordinary covalent bonds.
Ozone (O3) consists of three
oxygen atoms joined together. One of the lone pairs of electrons from one of
the oxygen atoms of an O2 molecule forms a new covalent bond with a
third oxygen atom:
An ammonium
ion (NH4+) is formed when a hydrogen ion joins an
ammonia molecule. A coordinate covalent bond forms between the electrons of the
nitrogen atom and the hydrogen ion:
Carbon
monoxide (CO) consists of one carbon atom and one oxygen atom joined together.
Two colvalent bonds are formed between the carbon and oxygen atoms. This leaves
carbon with only six valence electrons instead of its desired eight. So oxygen
uses one of its lone pairs to make a shared pair. Hence there is a triple bond
between the oxygen and carbon atoms:
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A hydronium
ion (H3O+) is formed when a hydrogen ion joins a water
molecule. A coordinate covalent bond forms between the electrons of the oxygen
atom and the hydrogen ion:
Allotropes of Oxygen
Allotropes are forms of the one element, in the same physical state, that have different physical properties such as hardness or density.
Intramolecular bonds are between atoms and they hold a molecule together. An example of an intramolecular bond is a covalent bond. Intermolecular bonds are between molecules, they hold the molecule together. Examples of intermolecular bonds include dispersion forces, dipole-dipole forces and hydrogen bonds.
Oxygen (O2) and ozone (O3) both have low melting points, boiling points and density because they are a covalently bonded, which means they have weak dispersion forces between their molecules. Ozone has higher density than oxygen gas because it is a heavier molecule. Ozone has higher melting and boiling points than oxygen gas and is less soluble in water because it has a double covalent bond as well as a coordinate covalent bond, which means it has stronger intermolecular bonds than oxygen gas, which only has a double bond.
Ozone (O3) is more reactive than oxygen gas (O2) because they have different structures. the double bond between oxygen gas atoms requires a lot of energy to break where as when ozone reacts an oxygen atom generally splits off quite easily, which leaves behind a stable O2 molecule.
Oxygen (O2) and ozone (O3) both have low melting points, boiling points and density because they are a covalently bonded, which means they have weak dispersion forces between their molecules. Ozone has higher density than oxygen gas because it is a heavier molecule. Ozone has higher melting and boiling points than oxygen gas and is less soluble in water because it has a double covalent bond as well as a coordinate covalent bond, which means it has stronger intermolecular bonds than oxygen gas, which only has a double bond.
Ozone (O3) is more reactive than oxygen gas (O2) because they have different structures. the double bond between oxygen gas atoms requires a lot of energy to break where as when ozone reacts an oxygen atom generally splits off quite easily, which leaves behind a stable O2 molecule.
Oxygen Freed Radicals
A free radical is a natural species that has an unpaired electron, which can be formed by splitting a molecule into two neutral fragments. Free radicals are usually very reactive because they are unstable and have incomplete electron shells. Free radicals are written in chemical equations with the unpaired electron shown as *,
O2 (g) → 2O* (g)
HOCL → H + CIO*
NO2 + sunlight → NO + O*
Concentration of O radicals is always very low in the atmosphere because of their high reactivity and they so when the concentration increases they quickly recombine to form O2.
Oxygen free radicals can be formed in the troposphere and in the stratosphere when sunlight is very intense and when concentrations of NO2 are well above clear-air levels. This happens when there is no breeze to disperse pollutants. The sunlight splits off an oxygen atom from the NO2 molecule and this oxygen atom becomes a free radical. Oxygen free radicals do not have a measured melting or boiling point because they are so reactive that whenever a high concentration of oxygen atoms is trying to be obtained, so that melting and boiling point can be measured, they recombine to form oxygen gas (O2). Oxygen free radicals exist as un-combined oxygen atoms that are highly reactive. Ozone is made up of two oxygen atoms sharing a double covalent bond and one of these atoms sharing a coordinate covalent bond with another oxygen atom. This makes ozone reactive as it easily decomposes to form oxygen gas. Oxygen gas (O2) is made up of two oxygen atoms joined together by a double covalent bond. This makes oxygen gas unreactive.
O2 (g) → 2O* (g)
HOCL → H + CIO*
NO2 + sunlight → NO + O*
Concentration of O radicals is always very low in the atmosphere because of their high reactivity and they so when the concentration increases they quickly recombine to form O2.
Oxygen free radicals can be formed in the troposphere and in the stratosphere when sunlight is very intense and when concentrations of NO2 are well above clear-air levels. This happens when there is no breeze to disperse pollutants. The sunlight splits off an oxygen atom from the NO2 molecule and this oxygen atom becomes a free radical. Oxygen free radicals do not have a measured melting or boiling point because they are so reactive that whenever a high concentration of oxygen atoms is trying to be obtained, so that melting and boiling point can be measured, they recombine to form oxygen gas (O2). Oxygen free radicals exist as un-combined oxygen atoms that are highly reactive. Ozone is made up of two oxygen atoms sharing a double covalent bond and one of these atoms sharing a coordinate covalent bond with another oxygen atom. This makes ozone reactive as it easily decomposes to form oxygen gas. Oxygen gas (O2) is made up of two oxygen atoms joined together by a double covalent bond. This makes oxygen gas unreactive.