How is it that you can have a bridging Hydrogen with Boron Complexes?

Question

Hydrogen only usually forms one bond but only with Boron complexes you can have two bridging Hydrogens with two Boron atoms.

Answer 1

The example of this type is B2H6.X-ray diffraction study reveal that it has a bridged structure.Two H are linked to B atom by covalent bond called terminal H while other two H by bridging H. These two H are involved in two three centred bond. Each bond consist of two electron one contributed by the H atom and d other by B atom. These two electron hold three atoms together(2 B atoms& 1 H atom).
REASON:- here B is SP3 hybridised and contain 1 empty orbital.Two hybrid orbital ob each B atom overlap with 1s orbital of two H atom to form normal B-H bond.Out of two hybridised orbital left, one contain an unpaired electron while d other is empty. The hybridised orbital of one B atom and the empty orbital belonging to other overlap at the sane time with 1s H orbital on both sides result in THREE CENTRED TWO ELECTRO BOND(3c-2e). Its shape is like banana and also known as banana bond. Hows it dude?

Answer 2

Boron atoms are electron deficient and although one can "bend" the octet rule with group three elements (B,Al, Ga) the boron atom would still prefer to attract as much electron density as possible.

The solution is for the boron atom to pick up additional electron density by delocalizing electron density from neighboring H atoms.

In Boron, this results in a dimeric molecular structure (B2H6) rather than a stable BH3. The total electron count from the hydrogen atoms is 2 and thus the term 3 center 2 electron bonds. If B only bonded to a single H, it would only pick up 1 electron in a standard covalent bond.

Answer 3

This is called a "three-electron" bond. It explains why "borane," BH3, is actually diborane, B2H6. The need (and the possibility) for such a bond comes from the fact that BH3 does not yield a stable structure according to the Lewis theory of the two-electron bond and the octet rule. It gives B a little more than just a sextet.

Answer 4

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