Elastic constants for hybrid organic-inorganic structures

[Inaoton]

Hello,
           I have a small query on the calculation of elastic constants for hybrid organic-inorganic structures.
         A hybrid organic-inorganic structure shows space group P1 in the builder while in the literature it says tetragonal. So in the calculation of elastic constants, the whole 21 independent elastic constants are calculated. How can I calculate the 5/6 elastic constants for the corresponding tetragonal structure?

[Ulrik G. Vej-Hansen]

In the Builder, you can go to Bulk Tools -> Lattice Parameters and specify the lattice type.