International
Tables for
Crystallography
Volume G
Definition and exchange of crystallographic data
Edited by J. R. Hester and B. McMahon

International Tables for Crystallography (2026). Vol. G. Early view chapter
https://doi.org/10.1107/97809553602060001011

Chapter 4.2 Core dictionary (coreCIF)


Index

Core dictionary version 3.3.0

_space_group.IT_coordinate_system_code

Name:
_space_group.IT_coordinate_system_code

Definition:

   
    A qualifier taken from the enumeration list identifying which
    setting in International Tables for Crystallography Volume A
    (2016) (IT) is used.  See IT Table 1.5.4.4, Section 2.1.3.15,
    Table 2.1.3.11 and Fig. 2.1.3.4.  This item is not
    computer-interpretable and cannot be used to define the
    coordinate system.

    Reference: International Tables for Crystallography (2016). Volume A,
     Space-group symmetry, edited by M. I. Aroyo, 6th ed.
     Chichester: John Wiley & Sons.

Type: Text


The data value must be one of the following:


b1
monoclinic unique axis b, cell choice 1, abc

b2
monoclinic unique axis b, cell choice 2, abc

b3
monoclinic unique axis b, cell choice 3, abc

-b1
monoclinic unique axis b, cell choice 1, c-ba

-b2
monoclinic unique axis b, cell choice 2, c-ba

-b3
monoclinic unique axis b, cell choice 3, c-ba

c1
monoclinic unique axis c, cell choice 1, abc

c2
monoclinic unique axis c, cell choice 2, abc

c3
monoclinic unique axis c, cell choice 3, abc

-c1
monoclinic unique axis c, cell choice 1, ba-c

-c2
monoclinic unique axis c, cell choice 2, ba-c

-c3
monoclinic unique axis c, cell choice 3, ba-c

a1
monoclinic unique axis a, cell choice 1, abc

a2
monoclinic unique axis a, cell choice 2, abc

a3
monoclinic unique axis a, cell choice 3, abc

-a1
monoclinic unique axis a, cell choice 1, -acb

-a2
monoclinic unique axis a, cell choice 2, -acb

-a3
monoclinic unique axis a, cell choice 3, -acb

abc
orthorhombic

ba-c
orthorhombic

cab
orthorhombic

-cba
orthorhombic

bca
orthorhombic

a-cb
orthorhombic

1abc
orthorhombic origin choice 1

1ba-c
orthorhombic origin choice 1

1cab
orthorhombic origin choice 1

1-cba
orthorhombic origin choice 1

1bca
orthorhombic origin choice 1

1a-cb
orthorhombic origin choice 1

2abc
orthorhombic origin choice 2

2ba-c
orthorhombic origin choice 2

2cab
orthorhombic origin choice 2

2-cba
orthorhombic origin choice 2

2bca
orthorhombic origin choice 2

2a-cb
orthorhombic origin choice 2

1
tetragonal or cubic origin choice 1

2
tetragonal or cubic origin choice 2

h
trigonal using hexagonal axes

r
trigonal using rhombohedral axes

Category:
space_group








































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