Search for Species Data by Structure or Substructure

Please draw the structure or substructure you wish to search for. Press the "Done" button when you are ready to search. If you are searching for the first time, please read these instructions and notes.

Notice: The drawing applet requires a Java capable browser to be run.


The structure drawing applet is designed to be a tool for drawing simple chemical structures and submitting them to a server. Actions possible with the applet depend on the mode (as indicated by the mode buttons and the text in the center of the bottom display line) the applet is in. In most modes an atom or a bond may be selected by placing the mouse over the item. On mice with more than one button all actions should be done with the right mouse button.

Draw mode

During draw mode, pressing the mouse button will add an atom of the currently selected type. To add an atom that is bonded to another one, select the existing atom, press the mouse button and drag the mouse to the desried location and release the mouse button to add the new atom.

A bond between existing atoms may be created by pressing the mouse button while one atom is selected and releasing it after the mouse has been dragged to the second atom. The type of bond may be changed by clicking on a selected bond. The drawing applet currently supports four types of bonds; single, double, triple, and aromatic.

Properties of individual atoms may be set through a dialog box obtained by double clicking on an atom.

Select Mode

Select mode allows an existing structures to be changed. Bonds and atoms may be changed in the same manner as in draw mode. Select mode also allows atoms to be used by dragging them with the mouse.

Erase Mode

Erase mode allows users to delete atoms and bonds by clicking on them.

Template Mode

Template mode allows pre-drawn templates to be embedded in a structure. Upon entering template mode a scrollable dialog with templates is displayed. Select the desired template by clicking on it. Once a template is selected, the template selection dialog will disappear and the template can be added to the structure by clicking on an atom or bond. Clicking on the drawing surface will place the template at the specified location.

Text Button

Click on the text button to see what the mol file for the structure looks like. This feature was added to aid in the development of the applet and has been left for users that might be interested in this type of information.

Done Button

When the structure is ready to be submitted to the server, the done button should be pressed. This button will bring up a dialog allowing the user to select full structure or substructure searching and to select the types of data required for the species. Pressing the "OK" button on this dialog starts the search.

When conducting a substructure search it is important to realize that atoms may be attached to a substructure at any loction where there are unbonded valence electrons. In oder to limit the number of matching species it may be of use to explicitly note the number of hydrogens on atoms in the substructure. For example a substructure search on C-C will match all species with a carbon–carbon single bond, while a search on H3C-CH2 will match all species with an ethyl group. As indicated below, the digit keys (0-9) can be used to set the number of hydrogen atoms bonded to the selected atom.

Keyboard Shortcuts

Several keys can be used as shortcuts for common editing operations. These keys will work in most modes and are listed in the table below.

SPACESwitches to draw mode
ESCSwitches to select mode
DELSwitches to erase mode
cSwitch to C
nSwitch to N
oSwitch to O
lSwitch to Cl
bSwitch to Br
fSwitch to F
iSwitch to I
pSwitch to P
sSwitch to S
kSwitch to Si
hSwitch to H
dSwitch to D
xSwitch to X (unknown)
.Set / remove radical center
0 to 9Set the number of hydrogens as specified
aIndicate that the number of hydrogens should be automatically computed


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Copyright for NIST Standard Reference Data is governed by the Standard Reference Data Act.

NIST, National Institute of Standards and Technology Material Measurement Laboratory Standard Reference
Data Program

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