Core dictionary (coreCIF) version 2.4.5
The mean hydrostatic pressure in kilopascals above which (*_gt) or below which (*_lt) the intensities were measured. These items allow for a pressure range to be given. _diffrn_ambient_pressure should always be used in preference to these items whenever possible.
The permitted range is 0.0 -> infinity
Related item: _diffrn_ambient_pressure (alternate)