NABH4 geometry
Started by SaintJude
Sorry, it really is just as tetrahedral as it looks in the picture.
BH3 is neutral. To add a hydrogen, you need two electrons to form a bond. Hydrogen natively has one. The other electron completes the bond and puts the negative charge on the molecule.
BH3 is neutral. To add a hydrogen, you need two electrons to form a bond. Hydrogen natively has one. The other electron completes the bond and puts the negative charge on the molecule.
Technically this is just BH4- geometry... 😛
But really, weird case with that formal charge if you haven't seen it before.
But really, weird case with that formal charge if you haven't seen it before.
Wait, are we talking about NaBH4 or just BH4, or is there no difference due to it being ionic (it is, right?).
BH4- looks tetrahedral to me.
BH4- looks tetrahedral to me.
The answer is definitely tetrahedral, for both electron group and molecular geometries. Were there a lone pair on the boron, the formal charge would be 3-, whereas a formal charge of 1- indicates one extra valence electron, and this is from the one electron in the fourth B-H bond which contributes to boron's valence (while the other contributes to the hydrogen's valence.)
Looking at the structure of a single formula unit of NaBH4 is more difficult; Lewis structures do not represent ionic bonds (like that between Na+ and BH4- using bond lines, and as a compound NaBH4 has several crystalline polymorphs. The question is definitely referring to the structure of the tetrahydroborate ion itself (BH4-).
Looking at the structure of a single formula unit of NaBH4 is more difficult; Lewis structures do not represent ionic bonds (like that between Na+ and BH4- using bond lines, and as a compound NaBH4 has several crystalline polymorphs. The question is definitely referring to the structure of the tetrahydroborate ion itself (BH4-).
