Among the following species, identify the iso-structural pairs.
NF3, NO−3, BF3, H3O+, N3H
[] and []
Lets first calculate the electron pairs of different compounds.
→NF3→ central atom → N (5 valence electrons)
3 Ligands
ep = (V+L+A−C)2=(5+3)2 = 4
The geometry will be tetrahedral [with 3bp and 1 lp]
→NO−3→ Central atom → N (5 - valence)
3 Ligands
ep = (V+L+A−C)2=(5+3+1)2 [VSEPR is not applied]
Try AVSEPR Theory
ep = (V+L+A−C)2=(5+1)2 = 3[ignore oxygen to compute ep]
Geometry is Trigonal Planar.
BF3→ Central atom → B (3 - valence)
3 Ligands
ep = (V+L+A−C)2=(3+3)2 = 3
Geometry is Trigonal planar
H3O+→ Central atom → 0 (6 - valence)
3 Ligands
Ep = (V+L+A−C)2=(6+3+0−1)2 = 4
Geometry is Tetrahedral →N3H⇒ Here H cannot be central atom Its structure comes out to be
H−N....−N....=N [Linear]
Therefore, [NO−3 and BF3 are isostructural] and[NF3 and H3O+ are isostructural]