Examples of polar covalent bond in the following topics:
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- Bond polarity exists when two bonded atoms unequally share electrons, resulting in a negative and a positive end.
- Bonds can fall between one of two extremes, from completely nonpolar to completely polar.
- The terms "polar" and "nonpolar" usually refer to covalent bonds.
- To determine the polarity of a covalent bond using numerical means, find the difference between the electronegativity of the atoms; if the result is between 0.4 and 1.7, then, generally, the bond is polar covalent.
- The hydrogen fluoride (HF) molecule is polar by virtue of polar covalent bonds; in the covalent bond, electrons are displaced toward the more electronegative fluorine atom.
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- Pure ionic bonding cannot exist: all ionic compounds have some degree of covalent bonding.
- The larger the difference in electronegativity between the two atoms involved in the bond, the more ionic (polar) the bond is.
- Bonds with partially ionic and partially covalent character are called polar covalent bonds.
- A covalent bond involves electrons being shared between atoms.
- This difference in charge is called a dipole, and when the covalent bond results in this difference in charge, the bond is called a polar covalent bond.
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- There are multiple kinds of attractive forces, including covalent, ionic, and metallic bonds.
- In the conventional presentation, bonds are designated as ionic when the ionic aspect is greater than the covalent aspect of the bond.
- Bonds that fall in between the two extremes, having both ionic and covalent character, are classified as polar covalent bonds.
- This bond is considered to have characteristics of both covalent and ionic bonds.
- Discuss the idea that, in nature, bonds exhibit characteristics of both ionic and covalent bonds
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- Molecular polarity is dependent on the presence of polar covalent bonds and the molecule's three-dimensional structure.
- Bond polarity: when atoms from different elements are covalently bonded, the shared pair of electrons will be attracted more strongly to the atom with the higher electronegativity.
- Such bonds are said to be 'polar' and possess partial ionic character.
- Molecular polarity: when an entire molecule, which can be made out of several covalent bonds, has a net polarity, with one end having a higher concentration of negative charge and another end having a surplus of positive charge.
- In molecules containing more than one polar bond, the molecular dipole moment is just the vector addition of the individual bond dipole moments.
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- These bonds include both strong intramolecular interactions, such as covalent and ionic bonds.
- When there is a greater electronegativity difference than between covalently bonded atoms, the pair of atoms usually forms a polar covalent bond.
- Again, polar covalent bonds tend to occur between non-metals.
- Bonds, especially covalent bonds, are often represented as lines between bonded atoms.
- Acetylene has a triple bond, a special type of covalent bond that will be discussed later.
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- Covalently sharing two electrons is also known as a "single bond."
- Covalent bonding interactions include sigma-bonding (σ) and pi-bonding (π).
- For atoms with equal electronegativity, the bond between them will be a non-polar covalent interaction.
- In non-polar covalent bonds, the electrons are equally shared between the two atoms.
- For atoms with differing electronegativity, the bond will be a polar covalent interaction, where the electrons will not be shared equally.
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- In general, for covalently bonded atoms having valence shell electron octets, if the number of covalent bonds to an atom is greater than its normal valence it will carry a positive charge.
- Such a covalent bond is polar, and will have a dipole (one end is positive and the other end negative).
- The degree of polarity and the magnitude of the bond dipole will be proportional to the difference in electronegativity of the bonded atoms.
- Thus a O–H bond is more polar than a C–H bond, with the hydrogen atom of the former being more positive than the hydrogen bonded to carbon.
- Methane is essentially non-acidic, since the C–H bond is nearly non-polar.
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- Unlike the alkyl halides, this group has two reactive covalent bonds, the C–O bond and the O–H bond.
- Consequently, the covalent bonds of this functional group are polarized so that oxygen is electron rich and both carbon and hydrogen are electrophilic, as shown in the drawing below.
- Indeed, the dipolar nature of the O–H bond is such that alcohols are much stronger acids than alkanes (by roughly 1030 times), and nearly that much stronger than ethers (oxygen substituted alkanes that do not have an O–H group).
- The most reactive site in an alcohol molecule is the hydroxyl group, despite the fact that the O–H bond strength is significantly greater than that of the C–C, C–H and C–O bonds, demonstrating again the difference between thermodynamic and chemical stability.
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- The ion-dipole force is an intermolecular attraction between an ion and a polar molecule.
- However, ion-dipole forces involve ions instead of solely polar molecules.
- Ion-dipole bonding is also stronger than hydrogen bonding.
- Ion-dipole forces are generated between polar water molecules and a sodium ion.
- These intermolecular ion-dipole forces are much weaker than covalent or ionic bonds.
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- Consequently, this functional group is polarized so that the carbon is electrophilic and the halogen is nucleophilic, as shown in the drawing below.
- The first of these is covalent bond strength.
- The strongest of the carbon-halogen covalent bonds is that to fluorine.
- Remarkably, this is the strongest common single bond to carbon, being roughly 30 kcal/mole stronger than a carbon-carbon bond and about 15 kcal/mole stronger than a carbon-hydrogen bond.
- The carbon-chlorine covalent bond is slightly weaker than a carbon-carbon bond, and the bonds to the other halogens are weaker still, the bond to iodine being about 33% weaker.