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Pearson's Crystal Data: Frequently Asked Questions

Besides this list of "Frequently asked questions" (FAQ), we would like to point you also to the function list or to the brochure. See links on the left side.

Q(uestion): How do I install Pearson's Crystal Data on a network?
A(nswer): This task is rather simple:
1. Install the Pearson's Crystal Data on one PC (the server) using the installation CDs you have obtained. Note that it is not possible to run Pearson's Crystal Data directly from the CDs!
2. Open the Windows Explorer on the server PC, right-click on the program directory of Pearson's Crystal Data (e.g. "C:\Program Files\Pearsons Crystal Data"), and share the program directory using an appropriate name (e.g. "PCD") (the network users do not need write access).
3. On a client PC, simply display the contents of the shared server directory (e.g. "PCD") in the Windows Explorer, and double-click on "PCD.exe" to run the Pearson's Crystal Data.

Q: ...I was wondering how it [Pearson's Crystal Data] relates to the classic 1991 2nd Edn of the Intermetallics Handbook. My interest is Intermetallic Compounds, usually containing a rare-earth element. Does the latest PCD contain all the information found in the 1991 Handbook?
A: Yes the CD-ROM contains all the data published in the classic 1991 edition. In addition the literature years from 1989 up to 2004(5) have been added. The coverage in Intermetallics is very comprehensive, in addition also the Inorganics have been added. (PV)

Q: [This refers to release 2009/10] In the scientific manual of ICSD [Inorganic Crystal Structure Database] is written: Scope and "Input philosophy" of ICSD: The database contains fully determined structures with atomic coordinates [...] and now contains 120794 structures[...]. PCD contains 180810 of which 69729 with "complete structure determined". So how can you write that PCD "achieves an ICSD coverage of more than 95 percent"?
A: PCD makes a more detailed grouping (cf. "Search/Quick search", field "Level of structural studies") of what ICSD calls "fully determined structures with atomic coordinates":
- complete structure determined: 69'729
- cell parameters determined and type with fixed coordinates: 25'334
- positions of non-H atom determined: 12'811
- average structure determined: 573
- part of atom coordinates determined: 306
- positions of non-H and part of H atoms determined: 294
- commensurate approximant determined: 58
- positions of non-H atoms in average structure determined: 29
Sum: 109'134.
95 percent of 120'794 ICSD entries are 114'755. The discrepancy between 114'755 - 109'134 = 5'621 comes from the fact that ICSD includes recently also sometimes such entries, which PCD groups under "cell parameters determined and structure type assigned": 63'061.

Q: How can I define another wavelength, e.g. Co rather than Cu, for a calculated powder pattern? Where is the dialog bar mentioned in the online help?
A: The dialog bar is not shown in the rather small powder pattern preview below the entry report (the usual view) but in the entry data full view. To change to this full view, simply double-click into the powder pattern, which opens the full view with four tabs "Data sheet" etc. You will find the settings for wavelength (and more) in the grey dialog bar left of the reflection list and diffraction diagram. Choose another wavelength from the drop-down list or enter a wavelength manually, then press the Enter key to update the powder pattern.