CERTIFICATION OF PERIODIC FINANCIAL REPORTS


     I, Peter Barna, Senior Vice President and Chief Financial
Officer of Crompton Corporation, certify, pursuant to 18 U.S.C.
Section 1350, as adopted pursuant to Section 906 of the
Sarbanes-Oxley Act of 2002 that:

     (1)  the Quarterly Report on Form 10-Q for the period ended
          March 31, 2003 (the "Periodic Report") which this
          statement accompanies fully complies with the requirements
          of Section 13(a) or 15(d) of the Securities Exchange Act
          of 1934; and

     (2)  the information contained in the Periodic Report fairly
          presents, in all material respects, the financial
          condition and results of operations of Crompton
          Corporation.



Dated: May 12, 2003

By:/s/Peter Barna
      Peter Barna
      Senior Vice President and
      Chief Financial Officer



This written statement accompanies the Periodic Report pursuant to
Section 906 of the Sarbanes-Oxley Act of 2002 and shall not, except
to the extent required by the Sarbanes-Oxley Act of 2002, be deemed
filed by Crompton Corporation for purposes of Section 18 of the
Securities Exchange Act of 1934.

A signed original of this written statement required by Section 906
has been provided to Crompton Corporation and will be retained by
Crompton Corporation and furnished to the Securities and Exchange
Commission or its staff upon request.