Non-ambient Chemical Crystallography
There are four logical parameters to consider within the confines of the diffractometer and single crystal diffraction experiment. The quadrant model for the crystal environment is a logical extension of the physical parameter space which can be applied to that environment. Non-ambient chemical crystallography exploits these four parameters either in tandem or individually and all in situ during the diffraction experiment.

Atmosphere
There is much, much more to come on this but for now why not start try reading about:
Temperature
There is much, much more to come on this but for now why not start try reading about:
Pressure
Again more to come on this.
External Stimuli
Again more to come on this.