Is there a reference list to show the initial value of the

bond length between 2 atoms? (e.g what is the bond length between the
pairs of atom (a, b), (c, d) (a, e) and etc. What is the minimum and
maximum value of the bond length?)

angle between 3 atoms? (e.g what is the angle between atom (a, b, c),
(c, d, e), (a, e, j) and etc).

torsion between 4 atoms? (e.g what is the torsion between atom (a, b, c,
d), (c, d, e, g), (a, e, j, k) and etc).

I need the above values to fill up a Z-matrix table and to create a
Z-matrix program so that I can input the information of a structure. If
the bond lengths and the angles are fixed, what parameters do I need to
calculate the torsion angles and to vary the torsion angles?

Are there any files and source codes in Avogadro distribution related to
my questions?

Is there a reference list to show the initial value of the

bond length between 2 atoms?

angle between 3 atoms?

torsion between 4 atoms?

I need the above values to fill up a Z-matrix table and to create a Z-matrix
program so that I can input the information of a structure. If the bond
lengths and the angles are fixed, what parameters do I need to calculate the
torsion angles and to vary the torsion angles?

Are there any files and source codes in Avogadro distribution related to my
questions?

There was a start on a z-matrix editor a while back, but I donâ€™t
believe that it was completed. For now, you can measure the bond
lengths, angles, and torsion/dihedral angles with the Measure tool.
There is also a roundabout way to get a full z-matrix:

Extensions > Gaussian > Format: Z-matrix

The z-matrix will be in the text field of the dialog window.