# Core CIF Dictionary version 2.3

# _refine_diff_density_

### Names

`'_refine_diff_density_max'`
`'_refine_diff_density_min'`
`'_refine_diff_density_rms'`
**Category:** refine

**Data type:** numb
(with optional s.u. in parentheses)

**Units:** e_A^-3^
( electrons per cubic angstrom)

### Definition

The largest, smallest and root-mean-square-deviation, in
electrons per angstrom cubed, of the final difference electron
density. The *_rms value is measured with
respect to the arithmetic mean density, and is derived from
summations over each grid point in the asymmetric unit of
the cell. This quantity is useful for assessing the
significance of *_min and *_max values, and also for
defining suitable contour levels.

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