Ownership Submission
FORM 4
Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).
UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940
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(Print or Type Responses)
1. Name and Address of Reporting Person *
ACKLEY ROBERT W
   2. Issuer Name and Ticker or Trading Symbol
CROMPTON CORP [CK] 		5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
_____ Director _____ 10% Owner
__X__ Officer (give title below) _____ Other (specify below)
Executive V.P. - Polymer Proc.
(Last)
(First)
(Middle)
CROMPTON CORPORATION, 1 EXTRUSION DRIVE		 3. Date of Earliest Transaction (Month/Day/Year)
04/05/2005
(Street)

PAWCATUCK, CT 06379		 4. If Amendment, Date Original Filed(Month/Day/Year)
 6. Individual or Joint/Group Filing(Check Applicable Line)
_X_ Form filed by One Reporting Person
___ Form filed by More than One Reporting Person
(City)
(State)
(Zip)
Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1.Title of Security
(Instr. 3)		 2. Transaction Date (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 3. Transaction Code
(Instr. 8)		 4. Securities Acquired (A) or Disposed of (D)
(Instr. 3, 4 and 5)		 5. Amount of Securities Beneficially Owned Following Reported Transaction(s)
(Instr. 3 and 4)		 6. Ownership Form: Direct (D) or Indirect (I)
(Instr. 4)		 7. Nature of Indirect Beneficial Ownership
(Instr. 4)
Code V Amount (A) or (D) Price
Common Stock 04/05/2005   J   11,985 A $ 8.3437 179,685 D  
Common Stock 04/05/2005   J   12,626 A $ 7.92 192,311 D  
Common Stock 04/05/2005   J   13,793 A $ 7.25 206,104 D  
Common Stock 04/05/2005   J   15,673 A $ 6.38 221,777 D  
Common Stock               2,601.4596 I By Wife
Common Stock 04/05/2005   J(1)   340.6794 A $ 0 3,700.07 I ESOP Trust
Common Stock 04/05/2005   J(2)   134 A $ 0 36,004.77 I LTIP Trust (1TA)
Common Stock 04/05/2005   J(3)   134 A $ 0 15,171.14 I LTIP Trust 1988
Common Stock               51.2041 I ESPP
Common Stock 04/05/2005   J(4)   72 A $ 0 19,340 I Restricted Stock Account

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
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Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security
(Instr. 3)		 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (Month/Day/Year) 3A. Deemed Execution Date, if any (Month/Day/Year) 4. Transaction Code
(Instr. 8)		 5. Number of Derivative Securities Acquired (A) or Disposed of (D)
(Instr. 3, 4, and 5)		 6. Date Exercisable and Expiration Date
(Month/Day/Year)		 7. Title and Amount of Underlying Securities
(Instr. 3 and 4)		 8. Price of Derivative Security
(Instr. 5)		 9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s)
(Instr. 4)		 10. Ownership Form of Derivative Security: Direct (D) or Indirect (I)
(Instr. 4)		 11. Nature of Indirect Beneficial Ownership
(Instr. 4)
Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares
NQ Stock Option (Right to Buy) $ 5.85             10/20/2004 11/19/2013 Common Stock 45,000   45,000 D  
NQ Stock Option (Right to Buy) $ 6.38             01/21/2004 02/20/2013 Common Stock 43,654   43,654 D  
NQ Stock Option (Right to Buy) $ 7.25             10/22/2003 11/21/2012 Common Stock 26,207   26,207 D  
NQ Stock Option (Right to Buy) $ 7.92             10/23/2002 11/22/2011 Common Stock 47,374   47,374 D  
NQ Stock Option (Right to Buy) $ 8.1562             10/31/2001 11/30/2010 Common Stock 75,000   75,000 D  
NQ Stock Option (Right to Buy) $ 8.3437             10/19/2000 11/19/2009 Common Stock 88,015   88,015 D  
NQ Stock Option (Right to Buy) $ 13             08/04/1999 12/18/2005 Common Stock 18,808   18,808 D  
NQ Stock Option (Right to Buy) $ 14.3438             08/05/1999 11/14/2008 Common Stock 50,000   50,000 D  
NQ Stock Option (Right to Buy) $ 14.5             08/04/1999 09/21/2006 Common Stock 72,416   72,416 D  
NQ Stock Option (Right to Buy) $ 16.875             08/04/1999 11/16/2006 Common Stock 20,000   20,000 D  
NQ Stock Option (Right to Buy) $ 26.4063             08/04/1999 11/07/2007 Common Stock 20,000   20,000 D  
ISO Stock Option (Right to Buy) $ 6.38 04/05/2005   J(5)     15,673 01/21/2005 01/21/2013 Common Stock 31,346 $ 6.38 15,673 D  
ISO Stock Option (Right to Buy) $ 7.25 04/05/2005   J(5)     13,793 10/22/2004 10/22/2012 Common Stock 13,793 $ 7.25 0 D  
ISO Stock Option (Right to Buy) $ 7.92 04/05/2005   J(5)     12,626 10/23/2003 10/23/2011 Common Stock 12,626 $ 7.92 0 D  
ISO Stock Option (Right to Buy) $ 8.3437 04/05/2005   J(5)     11,985 10/19/2002 10/19/2009 Common Stock 11,985 $ 8.3437 0 D  
ISO Stock Option (Right to Buy) $ 13             08/04/1999 10/18/2005 Common Stock 7,692   7,692 D  
ISO Stock Option (Right to Buy) $ 14.5             08/04/1999 08/21/2006 Common Stock 27,584   27,584 D  

Reporting Owners

Reporting Owner Name / Address Relationships
 Director  10% Owner  Officer  Other
ACKLEY ROBERT W
CROMPTON CORPORATION
1 EXTRUSION DRIVE
PAWCATUCK, CT 06379		       Executive V.P. - Polymer Proc.  

Signatures

 Robert W. Ackley   04/06/2005
**Signature of Reporting Person Date

Explanation of Responses:

* If the form is filed by more than one reporting person, see Instruction 4(b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
(1) These shares were acquired during the fiscal year pursuant to the Registrant's Employee Stock Ownership Plan and through reinvestment of dividends paid on the shares in this fund (ESOP Trust).
(2) These shares were acquired during the fiscal year pursuant to the Long Term Incentive Plan (LTIP Trust (1TA)) and through reinvestment of dividends paid on the shares in this fund.
(3) These shares were acquired during the fiscal year pursuant to the 1988 Long Term Incentive Plan and through reinvestment of dividends paid on the shares in this fund.
(4) These shares were acquired during the fiscal year pursuant to the 2004-2006 Long Term Incentive Plan and through reinvestment of dividends paid on the shares in this fund.
(5) Excercise of an Incentive Stock Option.

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