CheckCIF-PLAT101-110

PLAT101 Insufficient Number of Digits Given for SpecialPosition x-Coordinate

Fractions of the type 1/3 and 2/3 for the positional parameters of atoms in special positions should be provided with sufficient digits. (i.e. 0.66667 and 0.33333). Otherwise, they might be treated by the software as off the symmetryelement.

(http://journals.iucr.org/services/cif/checking/PLAT101.html)

警告原因：当原子处在特殊位置上且占有率为1/3或2/3时，需给出足够位数的小数。否则会被软件认为不处在对称元素上。102和103检查原因和处理方式相同。

解决策略：将相应占有率补足足够小数位数即可。

PLAT 102 Insufficient Number of Digits Given for SpecialPosition y-Coordinate

Fractions of the type 1/3 and 2/3 for the positionalparameters of atoms in special positions should be provided with sufficientdigits. (i.e. 0.66667 and 0.33333). Otherwise, they might be treated by thesoftware as off the nearly symmetry element.

(http://journals.iucr.org/services/cif/checking/PLAT102.html)

警告原因：当原子处在特殊位置上且占有率为1/3或2/3时，需给出足够位数的小数。否则会被软件认为不处在对称元素上。102和103检查原因和处理方式相同。

解决策略：将相应占有率补足足够小数位数即可。

PLAT 103 Insufficient Number of Digits Given for SpecialPosition z-Coordinate

Fractions of the type 1/3 and 2/3 for the positional parameters of atoms in specialpositions should be provided with sufficient digits. (i.e. 0.66667 and0.33333). Otherwise, they might be treated by the software as off the nearbysymmetry element.

(http://journals.iucr.org/services/cif/checking/PLAT103.html)

警告原因：当原子处在特殊位置上且占有率为1/3或2/3时，需给出足够位数的小数。否则会被软件认为不处在对称元素上。102和103检查原因和处理方式相同。

解决策略：将相应坐标补足足够小数位数即可。

PLAT104 Type_1 Test for additional translational symmetry [0, 1]

Check the reported crystal system against the reported space group. Alternatively, no crystal system was reported.

(http://journals.iucr.org/services/cif/checking/PLAT104.html)

例：PLAT104_ALERT_1_GThe Reported Crystal System is Inconsistent with      P21/n Check

警告原因：未在_space_group_crystal_system项中给出晶系的信息或者给出晶系信息同空间群信息不符。

解决策略：一般不会出现，为误操作。重新精修生成cif文件即可。

PLAT107 Type_2 Test validity of inversion twinning operation

Inversion twinning is meaningless in centrosymmetric spacegroup.

在中心对称空间群中，倒反孪晶是无意义的。

(http://journals.iucr.org/services/cif/checking/PLAT107.html)

PLAT108 Type_2 Test validity of the twinning operation

The SHELXL TWIN instruction matrix corresponds to a symmetry operation of the non-centrosymmetric Laue group of the crystal structure. This is not a valid twin operation.

SHELXL中的TWIN指令矩阵对应于晶体结构的非中心对称劳厄群的对称操作。这不是有效的孪晶操作。

(http://journals.iucr.org/services/cif/checking/PLAT108.html)

PLAT109 Type_2 Test validity of the twinning operation

The SHELXL TWIN instruction matrix corresponds to an inverted symmetry operation of the non-centrosymmetric Laue group of the crystal structure. The reported twinning factor is actually the Flack x value.

SHELXL中的TWIN指令矩阵对应于晶体结构的非中心对称劳厄群的倒反对称操作。报告的孪晶因子实际上是Flack系数x的值。

(http://journals.iucr.org/services/cif/checking/PLAT109.html)

PLAT110 Type_2 Test for additional translational symmetry [0, 1]

Tests for missed symmetry are done with ADDSYM, an extended MISSYM (C) clone. These tests warn for missed or possible higher (pseudo) symmetry in the structural model (i.e. based on the coordinate data). Close examination of the situation at hand is indicated in order to prove/disprove the issue (usually in combination with the reflection data). Report on potential (pseudo/real) lattice centering or cell halving.

Note: H-atoms and disordered atoms are not taken into account in the tests.

用ADDSYM(一个扩展的MISSYM (C)克隆体)来检查丢失的对称性。这些检查对结构模型(即基于坐标数据)中存在遗漏或可能更高(伪)对称性发出警告。为证明/反驳这一问题(通常与衍射数据结合)，需要对手头的情况进行仔细检查。报告潜在的(伪/实)晶格定心或晶胞减半。

注意：检查中不考虑氢原子和无序原子。

(http://journals.iucr.org/services/cif/checking/PLAT110.html)

警告原因：可能存在对称因素。

解决策略：使用Platon中的Addsym检查是否需要升空间群，否则需要给出合理解释。