Building and Optimizing Diborane B₂H₆.

To "build" diborane load "BH₃" twice from the library. To load the second BH₃ use ADD.Mol on the build menu. This will give


Run Mopac using defaults and the optimized structure should be



For cosmetic purposes you can add the two "missing" lines using the Mk.CONN function on the build menu. Use Mk.CONN twice each time select the H atom first.

How good is the result ?
Use the button in build mode to measure the bond lengths and angles and you should get the following.
B-H_ter 1.191 (Obs. 1.192)
B-H_br 1.331 (Obs. 1.329)
H_ter-B-H_ter 124.8 (Obs121.8)
H_br-B-H_br 97.2 (Obs 96.5)
The agreement between AM1 calaculations and experimental data is quite good.

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