Data Item _atom_site_anisotrop.U[2][2]

General

Item name
_atom_site_anisotrop.U[2][2]
Category name
atom_site_anisotrop
Attribute name
U[2][2]
Required in PDB entries
no
Used in current PDB entries
Yes, in about 20.7 % of entries

Item Description

The [2][2] element of the standard anisotropic atomic displacement matrix U, which appears in the structure-factor term as: T = exp{-2 pi2 sumi[sumj(Uij hi hj a*i a*j)]} h = the Miller indices a* = the reciprocal space cell lengths These matrix elements may appear with atomic coordinates in the ATOM_SITE category, or they may appear in the separate ATOM_SITE_ANISOTROP category, but they may not appear in both places. Similarly, anisotropic displacements may appear as either B's or U's, but not as both. The unique elements of the real symmetric matrix are entered by row.

Data Type

Data type code
float
Data type detail
float item types are the subset of numbers that are the floating numbers.
Primitive data type code
numb
Regular expression
-?(([0-9]+)[.]?|([0-9]*[.][0-9]+))([(][0-9]+[)])?([eE][+-]?[0-9]+)?
Units
angstroms_squared

Subcategories

Subcategory Name Subcategory Description
matrix The collection of elements of a matrix.

Aliases

Alias Item Name Dictionary Name Dictionary Version
_atom_site_aniso_U_22 cif_core.dic 2.0.1