The Solubility Parameters Section contains four fields for the following properties:

The Abbreviations Dialog shows the definitions of all the abbreviations used in Cranium and Synapse. To activate the dialog, select the Help menu's Abbreviations command. See here for documentation.

The three-term solubility parameter model, often referred to as the Hansen solubility parameter model, assigns three values to a chemical to characterize its dispersive, polar and hydrogen bonding nature. The model predicts that chemicals with similar values for these three values will be soluble with each other.

Representing the solubility parameter by the symbol δ, the symbols for each of the three terms are:

δd	Dispersive parameter
δp	Polar parameter
δh	Hydrogen bonding parameter

Using this notation, the similarity of two chemicals, a and b, can be measured by the Euclidean distance formula:

Thus if two chemicals have a small value for D, then they should be soluble with each other.

The Solubility Parameters Section contains four property fields and one compound graph field. Each property field contains a label, a datum control, an estimates control and a units control. The compound graph field contains three graphs.

1	Datum Control: displays the field's physical property's data value. A green triangle in the datum control's upper right corner indicates that additional data are available. (See below.)
2	Estimate Control: displays the field's physical property's estimated value.
3	Units Control: displays the current units for the field's physical property.
4	Graphs Control: the compound graphs field displays three solubility parameter graphs.

The four solubility parameters fields this section contain numerical values. Thus, they all appear similar and are edited in the same manner.

The Data column of each field displays a solubility parameter data value. The data value is displayed in the units shown in the Units column. A green triangle in the data control's upper right corner indicates that additional data are available. (See documentation on the Datum-Units-Reference All Data Dialog for details on managing data having different status.)

Clicking the right mouse button within the field's datum control activates the field's datum commands menu.

The menu's commands enable you to copy, cut and paste values to and from the data control. See Common Menu Commands for documentation on the commands commonly found on command menus. See below for documentation on this field's specific menu commands.

• Edit All Data: uses the All Data dialog to enable editing data having status values of passive, rejected or unknown. See Datum-Units-Reference All Data Dialog for documentation.)
• Edit Data: enables you to view and modify the solubility parameter datum's value, accuracy, units of measure, reference and comments. See Datum-Units-Reference Edit Dialog for detailed documentation.

  Before saving, the dialog runs a verification test checking that the entered solubility parameter value is greater than or equal 0. Cranium or Synapse will signal an error if the entered value fails a physical property verification test.

The Estimation Details dialog shows the estimated value, the technique used to generate the estimate, and any comments generated during the estimation. The dialog also has two buttons to provide more information about the technique used to generate the estimate:

• Tech Notes: displays the general notes associated with the estimation technique.
• Tech Ref: display the document associated with the technique's reference.

Clicking the right mouse button on the estimate control displays the commands menu.

The menu's commands enable you to copy values, clear values and manage the property's estimation techniques. See Common Menu Commands for documentation on the commands commonly found on command menus. See below for documentation on this field's specific menu commands.

• Compute Estimate: activates the Property Estimation dialog which enables you to estimate the current solubility parameter. The functionality of this command is similar to that of the Commands menu's Compute Estimates command. The key difference is that the estimates control's menu command limits the estimation to only the current physical property. See Estimating Chemical Properties for additional documentation.
• Select Technique: enables you to specify the estimation mode and the estimation technique used to estimate the current physical property. Selecting this command activates the Estimation Technique Information dialog.

  The dialog lists two estimation modes: Automatic and Manual. By default all estimations are initially set to Automatic Mode. Once you choose Manual Mode, the list of estimation techniques is enabled allowing you to choose any estimation technique known to the application. See documentation on Manual Techniques Dialog for details about manually selecting estimation techniques.
• Detail Estimate: activates the Details Dialog displaying information about the estimation technique used. See documentation on the Estimate-Units-Technique Dialog for details.

Note that values cannot be pasted into a field's estimated value control.

Selecting new units from the list and press the OK button changes the current units in which the property is displayed. (Note that all data are stored in their original units - changing the displayed units does not change any stored data.) The dialog's Std Units button displays the default units used by Cranium and Synapse for the current physical property. All estimated values are generated by Cranium and Synapse in standard units. (See documentation on the Property Units Dialog for additional details on changing property units.)

The units set via the Set Property Units dialog, accessed either from the Options menu's Set Units command or clicking on the Units control in a physical property field, are assigned for all documents in the application. For example, if you have three knowledge base documents open and then change the units of the total solubility parameter, all documents will update their total solubility parameter displays using the newly selected units.

Units are also stored in the application. The next time Cranium or Synapse starts, the set of units used in your last session will be used again.

The Solubility Parameter Section contains a compound graph control. This control contains three different graphs. You use the right hand side vertical scroll bar to switch between graphs.

1	Use the graph field's scroll bar to quickly switch between the section's three solubility parameter graphs.

Each graph displays a solute point, a solubility region, and solvent points.

1	Solute Point: the large blue square represents the solubility parameters of the current chemical, i.e., the solute.
2	Solubility Region: the green ellipse represents the region of points less than a target distance from the Solute Point. The default distance is 5 units. Solubility parameter theory states that chemicals whose solubility parameters are within this region should be good solvents for the solute.

Each solubility parameter graph shows solvents selected from the Solubility in Solvents Section.

3	Green Points: solvents that have high solubility for the current chemical, i.e., the solute, are drawn in green.
4	Yellow Points: solvents that have moderate solubility for the current chemical, i.e., the solute, are drawn in yellow.
5	Red Points: solvents that have low solubility for the current chemical, i.e., the solute, are drawn in red.

1	Axis Format Edit Button: the dialog shows the format in which the graphs' axes are displayed. Pressing the Edit Button activates the Number Format Dialog. The dialog enables you to change a number's formatting by changing the number of displayed decimal places and the number of exponent digits. Setting the exponent digits to 0, means that the number will not be displayed in exponential notation.
2	Axis Minimum: this control enables you to enter a numerical value for the axis minimum value or select 'Automatic' from the dropdown menu. If 'Automatic' is selected, the application will set the axis minimum to the minimum of the points being graphed or to a default minimum value if no points are present.
3	Axis Maximum: this control enables you to enter a numerical value for the axis maximum value or select 'Automatic' from the dropdown menu. If 'Automatic' is selected, the application will set the axis maximum to the maximum of the points being graphed or to a default maximum value if no points are present.
4	Divisions: this control enables you to enter the number of divisions shown on the axis.

The controls for editing the attributes of the Dispersive, Polar, and Hydrogen Bonding axes all function as described in steps 2, 3, and 4 above.

Clicking the right mouse button on a solubility parameter graph control displays the control's commands menu.

Each of these commands is documented below.

• Edit Solubility Constraints: activates the Solubility Parameters Graphs Options dialog.

  This dialog provides you with numerous controls that enable you to tailor the selection of solubility data to display, the allocation of good or poor solvents, the dimensions of the solubility ellipse, and other display options. See the Solubility Parameters Graph Constraints Dialog documentation for details.
• Edit Graph Attributes: activates the Solubility Parameters Graph Attributes Dialog which enables you to edit axis formats and set axis limits. This dialog is also activated by clicking the left mouse button on a solubility parameter graph. (See above).
• Analyze Solvents: activates the Solubility Parameter Graphs Examination Dialog. This dialog provides capabilities for identifying good solvents, designing solvent blends, and finding matching solvents. See the Solubility Parameters Graph Examination Dialog documentation for details.
• Transfer Graph: activates the Transfer Graph Values Dialog.
  This dialog enables you to transfer values from a solubility parameter graph to an xy graph in an XY Graph Document. See the Transfer Graph Values Dialog documetation for details.

• Copy Graph: copies an image of the graph onto the clipboard for pasting into other applications.

Topic	Description
Estimating Chemical Properties	a short video demonstrating how to estimate physical properties using either Synapse or Cranium.
Getting Started using Cranium	provides a quick tour of Cranium's capabilities including a discussion of structure editing.
Chemicals Chapter	the chemicals chapter contains numerous sections for entering and displaying data and estimates including the chemical structure section.