User Help

 

There are three parts to this database. The first part includes general information, such as the space group, cell parameters, Al/P ratio, template, and chemical formula; the second part, the structural characteristics, such as atomic coordinates, coordination state, connection environment, CSQ, and stacking sequence; and the third part, the simulated XRD pattern and references. Nearly every item in the database can be queried on the query page. All the searchable items are listed as below. Users can also search the database through any combination of these items. It should be noted that only items whose check boxes are checked will be recognized by the query program.

 

 

Classification Number:

Every structure in the database is classified with five numbers separated by full stop characters ("."). The first number denotes the dimension of the structure; the second and the third, the Al/P ratio in the form of prime numbers; the fourth number is the number of its space group in  Internal Tables For Crystallography; and the last is a serial number that discriminates the different structures within a category. These five numbers have a one-to-one correspondence with the structure. The query program will return the classification numbers for any inquiry. Users can find further detailed information about a structure through this code.

Example: search for a 2-D layered structure with an Al/P ratio of 3/4 in the space group P21/c:

 

 

Type Material (or Framework Type Code):

The name of the type material or of the framework type code for a specific structure. For example, typing "AlPO-5", "AlPO4-5", or "AFI" will return the structure of AlPO4-5. The name of the type material is not case sensitive.

Example: search for AFI-type structures:

 

 

Formula:

The chemical formula of the structure. This formula is usually taken from the published paper. The query program will return all the structures containing the elements the user has defined.

Example: search for all structures containing the element Co:

 

 

Template:

The chemical formula of the template molecule. Elements are usually given in alphabetical order. For transition metal complexes, the metal element is given first, followed by other elements in an alphabetical order. For example, CoC6H24N6 denotes Co(en)3.

Example: search for all structures templated by protonated ethane-1,2-diamine:

 

 

Al/P Ratio :

The Al/P ratio in the form of prime numbers. For example, an Al:P ratio of 3:4 is given as "3/4". For structures, especially for AlPO4 zeolites in which some Al or P atoms have be replaced with other elements, the Al/P ratio is still regarded as 1/1 since the degree of replacement is generally low. For example, CoAlPO-5 will be considered to have an Al/P ratio of 1/1.

Example: search for all structures with an Al/P ratio of 2/3:

 

 

Isomorphous Element:

If there is any isomorphous replacement, the element can be written here. For example, by typing "Co" in this text box, "1/1" in the Al/P ratio text box, and AFI in the Type Material text box, the query program will return Co-substituted AFI, i.e.,CoAlPO-5:

 

 

Space Group:

Only the space groups in standard settings are supported. For example, select "P21/c" to query structures in space group "P21/n".

Example: search for all structures in the space group P21/c:

 

 

Cell Parameters:

Unit cell parameters are in Angstroms and degrees. The first textbox is for the expected value of each item, and the second textbox is for the deviation. For example, by typing "8.0" and "0.1" in the two textboxes following a, structures with a in the range of 7.9 to 8.1 will be returned. The default deviation of the lattice length is 0.2 , and the default deviation of the lattice angle is 1.0 . The unit cell parameters might differ from those in the published papers because of different choices of space group settings.

Example: search for all structures with a hexagonal lattice.

 

 

Dimension:

Dimension of the structure. Selecting "3" for 3-D framework structures; "2" for 2-D layered structures; "1" for1-D chained structure; and "0" for 0-D clusters.

Example: search for all 2-D layered structures:

 

 

Coordination:

Al coordination. An Al-atom can be 4-, 5- or 6-coordinated. "M" denotes any non-Al atom. Since all P-atoms are 4-coordinated in our database, they are not listed here. In this field, "O" atoms are regarded as ligand atoms, and include both O-atoms and F-atoms.

Example 1: search for all structures with both 4- and 5-coordinated Al-atoms:

 

 

Example 2: search for all structures with ONLY 4- and 5-coordinated Al-atoms:

 

 

Connection:

Al or P connections with their neighbors. This can also be viewed as a detailed coordination description. Here "Ob" ("Fb") denotes a bridging O (F) atom, and "Ot" ("Ft"), a terminal O (F) atom. So do F atoms. In contrast to the coordination states defined above, O- and F-atoms are distinguished here.

Example: search for all structures with 4- and 6-coordinated Al atoms which are 4-connected by Ob atoms:

 

 

CSQ:

Coordination sequences. Only the first 10 shells are needed. Duplicate CSQ lines should be removed. The search is not sensitive to the order of the atoms.

Example: search for all structures with 1-D corner-sharing chains:

 

 

Layer Stacking Sequence:

Stacking sequences for layer structures.

Example: search for all layer structures with an AB stacking sequence:

 

 

Largest Ring:

The largest channel aperture. Only rings larger than 6-MR are considered.

Example: search for all structures with 12-ring apertures:

 

 

XRD pattern:

The first three peaks in the simulated XRD pattern. All data are given assuming an X-ray wavelength of 1.5418 (Cu Kα1,2). Only reflections with relative intensities greater than 0.001 are considered. The two textboxes are for the expected value and the allowed deviation. The default deviation is 0.2 2θ.

Example: search for all structures with the first 3 peaks at 7.5, 13, and 15 2θ (AlPO-5):

 

 

References:

References from which the structural data were obtained.

Example: search for the structure published in a paper in 1993: