Which of the following pairs of species are isostructural?

Step-by-step solution

Isostructural species have the same molecular shape. For NH ₃ : Central N has 5 valence electrons. It forms 3 bonds and has 1 lone pair. Shape: Trigonal pyramidal. For BF ₃ : Central B has 3 valence electrons. It forms 3 bonds and has 0 lone pairs. Shape: Trigonal planar. For SF ₄ : Central S has 6 valence electrons. It forms 4 bonds and has 1 lone pair. Shape: See-saw. For CH ₄ : Central C has 4 valence electrons. It forms 4 bonds and has 0 lone pairs. Shape: Tetrahedral. For BCl ₃ : Central B has 3 valence electr