**Definition:**

Residual factor for the reflections (with number given by _reflns.number_gt) judged significantly intense (i.e. satisfying the threshold specified by _reflns.threshold_expression) and included in the refinement. The reflections also satisfy the resolution limits established by _refine.ls_d_res_high and _refine.ls_d_res_low. This is the conventional R factor. See also _refine.ls_wR_factor_ definitions. sum | F(obs) - F(calc) | R = ------------------------ sum | F(obs) | F(obs) = the observed structure-factor amplitudes F(calc) = the calculated structure-factor amplitudes and the sum is taken over the specified reflections

**Type:** float

**Mandatory item:** no

The permitted range is [0.0, infinity)

**Related item: **_refine.ls_R_factor_obs (alternate)

**Category:** refine

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