The structure database is very convenient but by necessity incomplete. A more powerful approach is to build 3D crystals from the space group information. Here we give an example on how to build TiO2, also known as rutile.
Open the crystal builder: Click on the structure tool and select "From Space Group"
And the following window pops up
Rutile has the symmetry of space group 136
Enter 136 in the "Number" field
Note how the Browser reflects the change and also how the "Name" and "Lattice" values change
Now set the two lattice parameters as below
We still need to define the atomic coordinates. For starters click on the plus below "Coordinates"
In a book on crystal structures you can find that rutile has two sites occupied. The Ti atom is on the "a" site
Select the Ti atom and select the "a" site
The oxygens occupy the "f" site.
Click on the plus to add a site Change the atom type to "O" and the site to "f"
As you can see in the "Coords" column and the "Parameters" column, this site has an undetermined parameter "x". (It represents a symmetry line for this space group.) In the book you can find that for TiO2 "x=0.3".
Set "x" to 0.3
The final dialog looks like
Press "Apply" and if that looks any good press "Close"
