1)In industries diborane is prepared by the reaction between Boran trifluoride ( BF3 ) and sodium hydride ( NaH )
2BF3 + 6NaH ==> B2H6 + 6NaF [ 450 k ]
b)LaboratoryMethod:-
2)It is prepared by treating Boran trifluoride with LiAlH4 in dry ether .
4BF3 + 3LiAlH4 ==> B2H6 + 3LiF + 3AlF3
Structureofdiborane:-
Diborane ( B2H6 ) is an electron deficient compound .
In B2H6 the four hydrogens present in two BH2 groups are known as terminal hydrogen atoms ( Ht ) . The remaining two H-atoms are called bridged hydrogen atoms ( Hb ) .
In diborane the central atom is Boran .
Ground state Electronic configuration of Boran atom is 1s² , 2s² , 2p¹x , 2p0y , 2p0z
Excited state Electronic configuration of Boran atom is 1s² , 2s¹ , 2p¹x , 2p¹y , 2p0z [ sp³ hybridisation ] .
In excited state Boran atom undergoes sp³ hybridisation , as a result 4-sp³ hybrid orbitals are formed . Out of these four hybrid orbitals one hybrid orbital is vacant , the remaining are half filled orbitals .
Each Boran atom makes two sigma bonds with 1s-orbital of hydrogen atom .
These bonds are called terminal bonds or 2-centered-2-electron bonds .
The two central Boran atoms makes two bridge bonds with the hydrogen atoms . In brigde bond formation the vacant sp³ hybrid orbital of one Boran atom and 1s orbital of hydrogen atom and half filled sp³ hybrid orbital of another Boran atom are participated. These bonds are known as B-H-B Bridge bonds or Banana bonds or 3-centered-2-electron bonds .
The B-H Terminal bonds lie in the same plane and the B-H-B Bridge bonds lie perpendicular to the plane of two BH3 groups .
Answers & Comments
Answer:
Preparation of diborane :-
a) Industrial Method :-
1) In industries diborane is prepared by the reaction between Boran trifluoride ( BF3 ) and sodium hydride ( NaH )
2BF3 + 6NaH ==> B2H6 + 6NaF [ 450 k ]
b) Laboratory Method :-
2) It is prepared by treating Boran trifluoride with LiAlH4 in dry ether .
4BF3 + 3LiAlH4 ==> B2H6 + 3LiF + 3AlF3
Structure of diborane :-
Diborane ( B2H6 ) is an electron deficient compound .
In B2H6 the four hydrogens present in two BH2 groups are known as terminal hydrogen atoms ( Ht ) . The remaining two H-atoms are called bridged hydrogen atoms ( Hb ) .
In diborane the central atom is Boran .
Ground state Electronic configuration of Boran atom is 1s² , 2s² , 2p¹x , 2p0y , 2p0z
Excited state Electronic configuration of Boran atom is 1s² , 2s¹ , 2p¹x , 2p¹y , 2p0z [ sp³ hybridisation ] .
In excited state Boran atom undergoes sp³ hybridisation , as a result 4-sp³ hybrid orbitals are formed . Out of these four hybrid orbitals one hybrid orbital is vacant , the remaining are half filled orbitals .
Each Boran atom makes two sigma bonds with 1s-orbital of hydrogen atom .
These bonds are called terminal bonds or 2-centered-2-electron bonds .
The two central Boran atoms makes two bridge bonds with the hydrogen atoms . In brigde bond formation the vacant sp³ hybrid orbital of one Boran atom and 1s orbital of hydrogen atom and half filled sp³ hybrid orbital of another Boran atom are participated. These bonds are known as B-H-B Bridge bonds or Banana bonds or 3-centered-2-electron bonds .
The B-H Terminal bonds lie in the same plane and the B-H-B Bridge bonds lie perpendicular to the plane of two BH3 groups .