Which of the following doe not arrange itself into a tetrahedral environment when bonding in the solid state?

Question

SiO2
Co2
H2Se
H2o

Answer 1

In chemical symbols, upper and lower case letters are VERY important.
Co is cobalt
CO2 is carbon dioxide.
H2o is nothing, but H2O is water.

If you meant CO2, then that does not have a tetrahedral shape. All of the others do.