Why does -LSB- math -RSB- -LSB- Fe -LRB- CN -RRB- _ -LCB- 6 -RCB- -RSB- ^ -LCB- -3 -RCB- -LSB- / math -RSB- undergoes -LSB- math -RSB- d ^ -LCB- 2 -RCB- sp ^ -LCB- 3 -RCB- -LSB- / math -RSB- hybridisation , while -LSB- math -RSB- -LSB- Fe -LRB- H _ -LCB- 2 -RCB- O -RRB- _ -LCB- 6 -RCB- -RSB- ^ -LCB- 3 -RCB- -LSB- / math -RSB- undergoes -LSB- math -RSB- sp ^ -LCB- 3 -RCB- d ^ -LCB- 2 -RCB- -LSB- / math -RSB- , though both are paramagnetic and have octahedral geometry ?
What math comes after geometry ?