What are bond lengths and angles for picric acid?
I would suggest to take a crystal structure available for free from Crystallography Open Database, COD#5000146. The entry webpage already has a JSmol script loaded, so you should see the molecular structure loaded on a black area. Selecting RMB (right mouse button) -&gt; Measurements -&gt; Show Measurements allows you to measure linear and angular parameters with mouse clicks.

Alternatively, you can download the CIF-file (5000146.cif) and load it with any crystallographic viewer if you prefer to work offline. For beginners I'd recommend Mercury, there is a free version available for Windows, macOS and Linux:



N. B. The asymmetric unit in this structure contains two molecules of picric acids – with and without H-atoms. Obviously, you need the one with the protons assigned.