How is there co coordinate bond in BH4- show with structure
Dear student
The Boron needs a full outer shell of electrons (8), and it gains three, like you said, by three hydrogens bonding covalently with it. This makes BH3.
There are now four pair of electrons in the outer shell, and three of these pairs are being used to bond to the three hydrogen atoms. Now a hydrogen anion (negative) comes along, and it has NO electrons in its outer shell, when it needs two to become stable.
It shares the unused pair of electrons in the outer shell of the BH3, and a covalent bond is formed, except the only difference is that both the atoms come from the boron.
Because the hydrogen was an anion, and had a negative charge, this negative charge is transferred to the final atom which is therefore a [BH4-] atom.
This type of covalent bond is called a dative covalent bond, and it is where both of the bonding pair of electrons come from the same atom .
Hope it is clear
Regards
The Boron needs a full outer shell of electrons (8), and it gains three, like you said, by three hydrogens bonding covalently with it. This makes BH3.
There are now four pair of electrons in the outer shell, and three of these pairs are being used to bond to the three hydrogen atoms. Now a hydrogen anion (negative) comes along, and it has NO electrons in its outer shell, when it needs two to become stable.
It shares the unused pair of electrons in the outer shell of the BH3, and a covalent bond is formed, except the only difference is that both the atoms come from the boron.
Because the hydrogen was an anion, and had a negative charge, this negative charge is transferred to the final atom which is therefore a [BH4-] atom.
This type of covalent bond is called a dative covalent bond, and it is where both of the bonding pair of electrons come from the same atom .
Hope it is clear
Regards