Answer:

All Bond Lengths are Similar in Sf6

Explanation:

The bond length in a molecule is the average distance between the nuclei of any two bonded atoms in a molecule. The bond length is influenced by a number of factors, including the electronegativity of the atoms involved, the size of the atoms, and the electronic configuration of the molecule.

In Sf4, the bond lengths are not similar. This is because the molecule has a seesaw shape, with four bonding pairs and one lone pair of electrons, which causes distortion in the bond angles and lengths.

In Cr2O7^-2, the bond lengths are not similar either. This is because the molecule has a complex structure with different types of bonds, including double bonds, single bonds, and coordinate covalent bonds.

However, in Sf6, all bond lengths are similar. This is because the molecule has an octahedral shape, with six bonding pairs of electrons arranged symmetrically around the sulfur atom. The six S-F bonds are identical in length, and the molecule is highly symmetric.

Therefore, the correct answer is option (B) Sf6, as it is the only compound with all bond lengths being similar.

In sf6 , the hybridization is sp3d2. This means that the amount of s-orbital character in all the bonds will be the same and so the bond lengths will be the same. In Cr2O7(-2), there is an oxygen present between the 2 chromium atoms and 4 other oxygen atoms have double bonds with chromium along with 2 having a negative charge. So the bond length will not be the same as double bonds are smaller than single bonds due to stronger linking. sf4 has sp3d hybridization so clearly it is not equal.