Click here to see a 6 Kb gif of the Dos version of the program. Note the notation used to enter a molecular formula and note how the program can display up to seven formulas simultaneously. This picture also shows one of the three possible ways that standard deviations of results can be shown. At the bottom of the picture you can see one of the eleven on-line help screens and you can see one of the many possible 'caution' messages displayable by the program. (These messages can be toggled on and off)
(The screen captures were performed in windows using a windowed version of the Dos-based program. Of course, the font while running under Dos will look different than the one shown in the picture.)

Click here to see a 6 Kb gif of how the Dos version of the program displays percent compositions. The blue square is the cursor used to navigate among the formulas. Another one of the on-line help screens is also shown, this one showing many of the available abbreviations. Finally, this picture shows a second way that standard deviations may be shown.

 Click here to see a 7 Kb gif of the results of the percent solver feature. The user had entered a target of 1% for oxygen and 64% for chlorine, and the program calculated the best x to get the actual percent compositions as close to the target values as possible. This picture also shows the on-line help screen that discusses entering isotopes into formulas.

On-Line Help

Eleven screens of help available during program operation.

 

Smart Case Conversion

The program will automatically convert lowercase letters to uppercase where appropriate for ease of entering a formula. Exact case matching and non-conversion are available too.

 

Multi-Line Display

Display of up to seven formulas with their molecular weights simultaneously.

 

Percent Composition

Percent composition of up to seven formulas.

 

Parentheses Are Allowed

For example, (CH3)3CH2CH3. The program handles up to four layers of embedded parentheses.

 

Hydrates or other addended compounds are allowed

For example, FeCl3-6H2O is iron(III) chloride hexahydrate.

 

User-definable abbreviations for common parts of compounds. Default abbreviations are included as examples.

For example PhCl is C6H5Cl and HOac is CH3COOH

 

The MWTPATH environment variable may be set to avoid creation of duplicate MWT_ABBR.DAT files on the hard drive.

 

Isotopes are recognized

For example, ^13C means Carbon-13 and C6H5^18OH is heavy-oxygen (Oxygen-18) labeled phenol

 

Feature of weighting parts of a compound relative to the other parts.

For example: [.2Na]Cl would have a weight of 0.2*22.989768+35.4527=40.0507 or NaCl-[.5H2O] would have a weight of 22.989768+35.4527+0.5*(2*1.00794+15.9994)=67.4501

 

Percent Solver mode

Useful for finding the value of "x" in a compound that satisfies user-specified percent composition requirements.

 

Built in calculator that understands operator precedence

For example, 4*5-2*3 = 14; (23.43-2.64*3)/6 = 2.585; and 2+2^4=18

 

Optional display of time during program operation.

 

Accuracy of the final digit of the molecular weight and percent composition

Capability to set optional features at the command line when starting the program.

 

Finally, it's Freeware and can be copied freely in its fully functional form.

 

Other sites referencing this page or the MWT program are (This list is out of date):

 

• Simtel.net - filename mwt2_87.zip

 

• Ohio Center for Supercomputing FTP server under the filename mwt2_87.exe

 

• Kermit K. Murray's Mass Spec Software page

 

• Paul Thiessn's Home Page

 

• Laboratory Equipment, Supplies and Organizers

 

Freie University at Berlin Software List

 

• Freie University at Berlin Chemistry Department

•  

Standard Disclaimer

Last Modified April 17, 2002