**Definition:**

Residual factor R(Fsqd) for reflections that satisfy the resolution limits established by _refine.ls_d_res_high and _refine.ls_d_res_low and the observation limit established by _reflns.observed_criterion, calculated on the squares of the observed and calculated structure-factor amplitudes. sum|F~obs~^2^ - F~calc~^2^| R(Fsqd) = --------------------------- sum|F~obs~^2^| F~obs~^2^ = squares of the observed structure-factor amplitudes F~calc~^2^ = squares of the calculated structure-factor amplitudes sum is taken over the specified reflections

**Type:** float

**Mandatory item:** no

The permitted range is [0.0, infinity)

**Category:** refine

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