Option (D) is the incorrect statement.

Diborane (B₂H₆) features a distinctive structure with four terminal B-Hᵗ bonds and two bridging B-Hᵇ bonds, confirmed by electron diffraction studies.​

Option Analysis

(A) Correct

The B-Hᵗ (terminal hydrogen) bond operates as a standard two-center two-electron (2c-2e) bond, where two electrons are shared between one boron and one hydrogen atom.​

(B) Correct

The B-Hᵇ (bridged hydrogen) bond forms a three-center two-electron (3c-2e) bond, known as a banana bond, involving two electrons delocalized across two boron atoms and one bridging hydrogen.​

(C) Correct

Terminal B-Hᵗ bond length measures 1.19 Å, while bridged B-Hᵇ bonds extend to 1.33 Å, making bridged bonds longer due to their weaker, multicenter nature.​

(D) Incorrect

This repeats the content of option (A) exactly, providing no new information and thus qualifying as redundant or erroneous in the context of identifying a unique incorrect statement.​

Diborane molecule (B₂H₆), a key electron-deficient boron hydride, showcases unique bonding vital for CSIR NET Life Sciences and chemistry exams. Its structure includes terminal B-Ht bonds (1.19 Å, 2c-2e) and longer bridged B-Hb bonds (1.33 Å, 3c-2e), distinguishing it from typical covalent compounds.​

Key Bonding Features

• Terminal Bonds (B-Ht): Form conventional 2c-2e bonds, stronger and shorter at 1.19 Å.​

• Bridged Bonds (B-Hb): 3c-2e banana bonds, weaker and longer at 1.33 Å.​

• Hybridization: Each boron adopts sp³ hybridization, yielding D₂h symmetry.​

Common Exam Misconceptions

In multiple-choice questions on diborane molecule, options repeating correct facts like “B-Ht bond is a two-center two-electron bond” signal the incorrect choice, as seen in Q. No 18. Bridged bonds exceed terminal in length, affirming option (C).​

This diborane structure analysis aids competitive prep, emphasizing bond distance differences for accurate answers.​