In the following molecule (1-(4-fluorophenyl)-4-[[1-(2-methoxyethyl)tetrazol-5-yl]-phenyl-methyl]-piperazine)
I have seen its 3D structure using Jmol, and I see that both nitrogens on the middle ring have either tetrahedral or trigonal pyramidal geometry. I get this, no problem. However, the ring that is made of four nitrogens is entirely planar. Shouldn't it also have some trigonal pyramidal nitrogens too? As for instance, the N on the point connecting to the -OH chain, it has 2 bonds and one unshared pair of electrons, yet it is still planar!