because of 5 volt pairs. Basic shape is trigonal bi pyramidal. Basic shape is trigonal bi pyramidal. Now in this case all the bonds are not equivalent. In this case of linear trigonal, planar, tetrahedral all the bonds are equivalent. But in this case there are two types of bonds. First is the bonds in the trigon. These are called equitriol bonds. These are called equitriol bonds. E4, equitriol bonds and these two are called axial bonds. Equitriol bonds and axial bonds. Now see in the equitriol, these are 3. So this axial bond formed 390 degree angle with the 3 bonds 90 degree bond pair bond pair repulsion on axial bonds. So, this is called axial bond. So, this is called axial bond or 3. But same 90 degree bond pair bond pair repulsion on equatorial bonds are only 2. Because equitriol bonds, there are 2 90 degree repulsion because equitriol bonds are 90 degree with the axial bonds and axial bonds are 90 degree with equitriol bonds. That is why axial bonds are longer than equitriol bonds. Axial bonds are longer than equitriol bonds. So, pulsion on axial bond is more than on equitriol bonds. So, if we have lone pair, then lone pair of cubite equitriol positions because repulsion on equitriol bonds is less. For example, if we have 4 bond pairs and 1 lone pair, then lone pair is on the equitriol position. This is called C. This shape is known as C. So, if we have 2 lone pairs, then again 2 lone pairs are on equitriol bonds because of these lone pairs, 1 pair slightly bent. So, this is called bent T shaped. See, it is a T if we run the same way. So, this is called lone pairs are on equitriol bonds because of these lone pairs, 1 pair slightly bent. So, this is called bent T shaped. See, it is a T if we rotate it, it will become a T. If we rotate it, it will become C. So, now, if we have all the 3 lone pairs, all the 3 positions, equitriol positions are occupied by lone pairs. So, shape is linear.