PROC-NAME: DENSX01 Type_1

PURPOSE: To check that the _exptl_crystal_density_meas matches the _exptl_crystal_density_diffrn.

PROCEDURE:

CALCULATE

RD = _exptl_crystal_density_diffrn / _exptl_crystal_density_meas

TEST

IF RD is 0.80 < > 1.20 issue ALERT A

? ? ? ?? "Alert A The ratio of the calculated to measured crystal density lies outside the range 0.80 < > 1.20"

RD is 0.90 < > 1.10 issue ALERT B

? ? ? ?? "Alert B The ratio of the calculated to measured crystal density lies outside the range 0.90 < > 1.10"

RD is 0.95 < > 1.05 issue ALERT C

? ? ? ?? "Alert C The ratio of the calculated to measured crystal density lies outside the range 0.95 < > 1.05"

? ? ? ? The calculated density given in the CIF differs significantly from the experimentally measured density quoted in the CIF. Check that you have measured, calculated and entered the densities correctly and that in your calculations you have allowed correctly for all distinct moieties present, including any solvent and all H atoms, and not the contents implied by the model if there are differences due to the omission of a few H atoms or solvent atoms.

(http://journals.iucr.org/services/cif/checking/DENSX_01.html)

目的：檢查_exptl_crystal_density_meas是否與_exptl_crystal_density_diffrn相匹配。

過程：

計(jì)算

RD = _exptl_crystal_density_diffrn / _exptl_crystal_density_meas

檢查

若RD小于0.80或者大于1.20，則發(fā)布A級(jí)警告

? ? ? ?? "Alert A The ratio of the calculated to measured crystal density lies outside the range 0.80 < > 1.20"

若RD小于0.90或者大于1.10，則發(fā)布B級(jí)警告

? ? ? ?? "Alert B The ratio of the calculated to measured crystal density lies outside the range 0.90 < > 1.10"

若RD小于0.95或者大于1.05，則發(fā)布C級(jí)警告

? ? ?? ? "Alert C The ratio of the calculated to measured crystal density lies outside the range 0.95 < > 1.05"

? ? ? ? CIF中給出的密度計(jì)算值與CIF中引用的密度實(shí)驗(yàn)測(cè)量值顯著不同。檢查是否已正確測(cè)量，計(jì)算和輸入密度值，并且再計(jì)算中是否正確允許所存在的所有不同部分，包括任何溶劑和所有氫原子，若由于刪除了一些氫原子或溶劑原子而存在差異，則不應(yīng)與模型所暗示的內(nèi)容相對(duì)應(yīng)。

例：DENSX01_ALERT_1_A The ratio of the calculated to measured crystal density lies outside the range 0.80 <> 1.20

Calculated density = 1.753

Measured density = 0.000

警告原因：晶體密度的計(jì)算值與測(cè)試值的比值超出限定范圍。

解決策略：將CIF中“_exptl_crystal_density_meas”后的“0”改為“?”。