CheckCIF-PLAT331-338

PLAT331 Type_2 Check Average Phenyl C-C

The standard average C-C bond distance in a phenyl ring is 1.395 Angstrom. The average ring distance may be smaller due to large thermal motion or incorrect cell dimensions.

苯环中C-C键键长的标准平均键长为1.395 Å。该平均键长可能由于大的热振动或不正确的晶胞尺寸而导致过短。

(http://journals.iucr.org/services/cif/checking/PLAT331.html)

警告原因：苯环中平均键长太短。

解决策略：可用AFIX 66对其进行限制。

PLAT332 Type_2 Check Phenyl C-C Range

The standard average C-C in a phenyl ring is 1.395 Angstrom. Bond distances in the ring are expected to vary only slightly due to thermal motion or substituent effects. Large deviations are likely due to data or model errors.

苯环中C-C键键长的标准平均键长为1.395 Å。其键长由于热振动或取代基效应仅允许极小的差异。偏离过大可能由于数据或模型错误。

(http://journals.iucr.org/services/cif/checking/PLAT332.html)

警告原因：苯环中平均键长太短或太长。

解决策略：可用AFIX 66对其进行限制。若因为数据太差，则需要重新收集数据。

PLAT333 Type_2 Check Average in Multiple Substituted Benzene Type C-C

The standard average C-C bond distance in a flat six carbon atom containing aromatic ring is 1.395 Angstrom. The actual average ring distance may be larger than expected due to substituents such as '=O', single bonds or systematic errors in the cell dimensions (E.g. when the wrong wavelength is used in the derivation of the cell parameters).

含平面六碳原子的芳环的标准平均C-C键键长为1.395 Å。该实际平均键长可能由于存在诸如“=O”或单键取代基或晶胞尺寸的系统误差(例如，当在晶胞参数的推导中使用了错误的波长时)而大于预期值。

(http://journals.iucr.org/services/cif/checking/PLAT333.html)

警告原因：六碳芳环中平均键长太短或太长。

解决策略：可用DFIX命令对其进行限制。若因为数据太差，则需要重新收集数据。

PLAT334 Type_2 Check Average in Multiple Substituted Benzene Type C-C

The standard average C-C bond distance in a benzene ring is 1.395 Angstrom. The average ring distance may be smaller due to large thermal motion, substituents such as '=O' or incorrect cell dimensions.

苯环中C-C键键长的标准平均键长为1.395 Å。该平均键长可能由于大的热振动、存在诸如“=O”取代基或不正确的晶胞尺寸而导致过短。

(http://journals.iucr.org/services/cif/checking/PLAT334.html)

例：PLAT334_ALERT_2_C Small Average Benzene C-C Dist. C23 -C28

警告原因：苯环上C23-C28距离略短。

解决策略：检查是否需要无序处理，用DFIX限制C23-C28距离后精修。

PLAT335 Type_2 Check Multiple Substituted Benzene Type C-C Range

The standard average C-C bond distance in a benzene ring is 1.395 Angstrom. Bond distances in the ring are expected to vary only slightly when due to substituent effects (exceptions include =O substituents). Large deviations may indicate data or model errors.

(http://journals.iucr.org/services/cif/checking/PLAT335.html)

例：PLAT335_ALERT_2_G Check Large C6 Ring C-C Range C015 -C01 0.20 Ang

警告原因：C6偏移苯环环距离较大。

解决策略：将此苯环加FLAT限制后精修。

PLAT336 Type_2 Check Unusual Bond Distance

Check this bond distance.

键长该键键长。

(http://journals.iucr.org/services/cif/checking/PLAT336.html)

警告原因：结构中存在不正常键长的键。

解决策略：若存在无序，则进行无序处理。也可以用DFIX对其键长进行限制。

PLAT338 Type_4 Check Average Torsion Angle in cyclo-hexane ring

Cyclohexane moieties should have be significantly puckered as measured by the average torsion angle tau. Unresolved disorder generally results in flattened rings and elongated displacement ellipsoids. A disorder model should be included in the calculations.

通过平均扭转角τ(tau，希腊字母的第十九个字母)测试，环己烷部分应明显起皱。未解决的无序通常导致扁平环或拉长的位移椭球。计算中应包括无序模型。

(http://journals.iucr.org/services/cif/checking/PLAT338.html)

警告原因：结构中环己烷变形严重。

解决策略：仔细检查，肯能需要对其进行无序处理。