SC TO-T/A

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE TO

Tender Offer Statement Under Section 14(d)(1) or 13(e)(1)
of the Securities Exchange Act of 1934
(Amendment No. 23)

ENGELHARD CORPORATION
(Name of Subject Company)

IRON ACQUISITION CORPORATION
a wholly owned subsidiary of
BASF AKTIENGESELLSCHAFT
(Names of Filing Persons—Offeror)

Common Stock, Par Value $1.00 Per Share
(Title of Class of Securities)

292845104
(CUSIP Number of Class of Securities)

Hans-Ulrich Engel
Iron Acquisition Corporation
100 Campus Drive
Florham Park, NJ 07932
(973) 245-6000

(Name, Address and Telephone Number of Persons Authorized
to Receive Notices and Communications on Behalf of Filing Persons)

Copy to:

Dr. Joerg Buchmueller
BASF Aktiengesellschaft
67056 Ludwigshafen
Germany
(+49 621) 604-8230 Peter D. Lyons, Esq.
Clare O'Brien, Esq.
Alberto Luzarraga, Jr., Esq.
Shearman & Sterling LLP
599 Lexington Avenue
New York, New York 10022
(212) 848-4000

CALCULATION OF FILING FEE

Transaction Valuation*	Amount of Filing Fee**
$5,260,005,738.00	$562,820.61

*

Estimated for purposes of calculating the amount of the filing fee only. Calculated by multiplying $39.00, the per share tender offer price, by 134,871,942 the sum of (i) the 124,011,840 outstanding shares of Common Stock as of May 5, 2006 (according to the Definitive Proxy Statement on Schedule 14A filed by Engelhard Corporation on May 12, 2006), and (ii) the 10,860,102 shares of Common Stock subject to outstanding options and stock units as of December 31, 2005 (according to the Annual Report on Form 10-K for the period ended December 31, 2005 filed by Engelhard Corporation).

**

Calculated as 0.0107% of the transaction value.

ý

Check the box if any part of the fee is offset as provided by Rule 0-11(a)(2) and identify the filing with which the offsetting fee was previously paid. Identify the previous filing by registration statement number, or the Form or Schedule and the date of its filing.

Amount Previously Paid:	$15,461.29	Filing Party:	Iron Acquisition Corporation
Form or Registration No.:	Schedule TO	Date Filed:	May 22, 2006
Amount Previously Paid:	$29,432.10	Filing Party:	Iron Acquisition Corporation
Form or Registration No.:	Schedule TO	Date Filed:	May 1, 2006
Amount Previously Paid:	$517,927.22	Filing Party:	Iron Acquisition Corporation
Form or Registration No.:	Schedule TO	Date Filed:	January 9, 2006

Check the box if the filing relates solely to preliminary communications made before the commencement of a tender offer.

Check the appropriate boxes to designate any transactions to which the statement relates:

ý

third-party tender offer subject to Rule 14d-1.

o

issuer tender offer subject to Rule 13e-4.

o

going-private transaction subject to Rule 13e-3.

o

amendment to Schedule 13D under Rule 13d-2.

Check the following box if the filing is a final amendment reporting the results of the tender offer: ý

        This Amendment No. 23 (this "Amendment") amends and supplements the Tender Offer Statement on Schedule TO originally filed on January 9, 2006, as amended by Amendments No. 1 through 22 (as so amended, the "Schedule TO") by Iron Acquisition Corporation, a Delaware corporation ("Purchaser") and a wholly owned subsidiary of BASF Aktiengesellschaft, a stock corporation organized under the laws of the Federal Republic of Germany ("Parent"). The Schedule TO relates to the offer by Purchaser to purchase all the issued and outstanding shares of common stock, par value $1.00 per share (the "Common Stock"), of Engelhard Corporation, a Delaware corporation (the "Company"), and the associated Series A Junior Participating Preferred Stock purchase rights (the "Rights," and together with the Common Stock, the "Shares") issued pursuant to the Rights Agreement, dated as of October 1, 1998, between the Company and ChaseMellon Shareholder Services, L.L.C., as Rights Agent (the "Rights Agreement"), for $39.00 per Share, net to the seller in cash (subject to applicable withholding taxes), without interest, upon the terms and subject to the conditions set forth in the Amended and Restated Offer to Purchase dated May 9, 2006 (together with any amendments or supplements thereto, the "Offer to Purchase"), and in the accompanying Letter of Transmittal (as may be amended and supplemented from time to time, the "Letter of Transmittal", and together with the Offer to Purchase, the "Offer"). Except as specifically provided herein, this Amendment does not modify any of the information previously reported on the Schedule TO.

Item 8. Interest in the Securities of the Subject Company.

Item 11. Other Information.

        Items 8 and 11 of the Schedule TO are hereby amended and supplemented as follows:

"At 12:00 midnight, New York City time, on June 8, 2006, the subsequent offering period expired without extension. Based on information provided by the Depositary, as of 8:00 p.m., New York City time, on June 8, 2006, a total of 113,489,680 Shares had been tendered pursuant to the Offer and during the pendency of the subsequent offering period, representing more than 90% of the outstanding Shares based upon 124,256,578 outstanding Shares as of May 25, 2006, as reported to Purchaser by the Company.

In accordance with applicable law, Parent and Purchaser will take all necessary actions to promptly effect the Merger."

        The press release announcing the expiration of the subsequent offering period is attached hereto as Exhibit (a)(51).

Item 12. Material to Be Filed as Exhibits.

        Item 12 of the Schedule TO is hereby amended and restated as follows:

(a)(1)	Offer to Purchase dated January 9, 2006.*
(a)(2)	Form of Letter of Transmittal.*
(a)(3)	Form of Notice of Guaranteed Delivery.*
(a)(4)	Form of Letter from Lehman Brothers Inc. to Brokers, Dealers, Commercial Banks, Trust Companies and Other Nominees.*
(a)(5)	Form of Letter to Clients.*
(a)(6)	Form of Guidelines for Certification of Taxpayer Identification Number on Substitute Form W-9.*
(a)(7)	Summary Advertisement as published in The Wall Street Journal on January 9, 2006.*
(a)(8)	Press Release issued by Parent on January 9, 2006.*
(a)(9)	Press Release issued by Parent on January 3, 2006.*
(a)(10)	Analyst presentation, dated January 3, 2006.*
(a)(11)	Text of email to U.S. employees of BASF Aktiengesellschaft, dated January 3, 2006.*
(a)(12)	Transcript of Conference Call, dated January 3, 2006.*
(a)(13)	Transcript of Interview with Dr. Kurt Bock.*

(a)(14)	Press Release issued by Parent on January 24, 2006.*
(a)(15)	Press Release issued by Parent on January 27, 2006.*
(a)(16)	Press Release issued by Parent on February 6, 2006.*
(a)(17)	Transcript of Analyst Conference Call, dated February 22, 2006.*
(a)(18)	Transcript of Media Conference Call, dated February 22, 2006.*
(a)(19)	Speech by Dr. Jürgen Hambrecht, dated February 22, 2006.*
(a)(20)	Speech by Dr. Kurt Bock, dated February 22, 2006.*
(a)(21)	Analyst presentation by Dr. Jürgen Hambrecht, dated February 22, 2006.*
(a)(22)	Analyst presentation by Dr. Kurt Bock, dated February 22, 2006.*
(a)(23)	Press Release issued by Parent on February 23, 2006.*
(a)(24)	Press Release issued by Parent on March 6, 2006.*
(a)(25)	Press Release issued by Parent on March 16, 2006.*
(a)(26)	Press Release issued by Parent on April 17, 2006.*
(a)(27)	Press Release issued by Parent on April 26, 2006.*
(a)(28)	Press Release issued by Parent on May 1, 2006.*
(a)(29)	Transcript of Dr. Kurt Bock's remarks at the 1st Quarter Analyst Conference Call and Excerpt of Q&A related to Offer, dated May 4, 2006.*
(a)(30)	Interim Report, dated May 4, 2006.*
(a)(31)	Speech by Dr. Jürgen Hambrecht, dated May 4, 2006.*
(a)(32)	Amended and Restated Offer to Purchase dated May 9, 2006.*
(a)(33)	Form of Amended and Restated Letter of Transmittal.*
(a)(34)	Form of Amended and Restated Notice of Guaranteed Delivery.*
(a)(35)	Form of Amended and Restated Letter from Lehman Brothers Inc. to Brokers, Dealers, Commercial Banks, Trust Companies and Other Nominees.*
(a)(36)	Form of Amended and Restated Letter to Clients.*
(a)(37)	Investor Presentation.*
(a)(38)	Definitive Proxy Statement, dated May 12, 2006 (incorporated by reference to the Schedule 14A filed with the Securities and Exchange Commission on May 12, 2006).*
(a)(39)	Press Release issued by Parent on May 22, 2006.*
(a)(40)	Press Release issued by Parent on May 23, 2006.*
(a)(41)	Letter to Stockholders of the Company, dated May 23, 2006.*
(a)(42)	Investor Presentation, dated May 23, 2006.*
(a)(43)	Press Release issued by Parent on May 24, 2006.*
(a)(44)	Supplement to the Amended and Restated Offer to Purchase, dated May 30, 2006.*
(a)(45)	Form of Revised Letter of Transmittal.*
(a)(46)	Form of Revised Notice of Guaranteed Delivery.*
(a)(47)	Form of Revised Letter from Lehman Brothers Inc. to Brokers, Dealers, Commercial Banks, Trust Companies and Other Nominees.*
(a)(48)	Form of Revised Letter to Clients.*
(a)(49)	Press Release issued by Parent on May 30, 2006.*
(a)(50)	Press Release issued by Parent on June 6, 2006.*
(a)(51)	Press Release issued by Parent on June 9, 2006.
(b)	None.
(d)(1)	Agreement and Plan of Merger, dated May 30, 2006, among Parent, Purchaser and the Company.*
(g)	None.
(h)	None.

*

Previously filed

        After due inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

Dated: June 9, 2006

IRON ACQUISITION CORPORATION
By:	/s/  HANS-ULRICH ENGEL Name: Hans-Ulrich Engel Title: President

        After due inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

Dated: June 9, 2006

BASF AKTIENGESELLSCHAFT
By:	/s/  DR. JÜRGEN HAMBRECHT Name: Dr. Jürgen Hambrecht Title: Chairman of the Board of Executive Directors
By:	/s/  DR. KURT BOCK Name: Dr. Kurt Bock Title: Member of the Board of Executive Directors

EXHIBIT INDEX

Exhibit No.

(a)(1)	Offer to Purchase dated January 9, 2006.*
(a)(2)	Form of Letter of Transmittal.*
(a)(3)	Form of Notice of Guaranteed Delivery.*
(a)(4)	Form of Letter from Lehman Brothers Inc. to Brokers, Dealers, Commercial Banks, Trust Companies and Other Nominees.*
(a)(5)	Form of Letter to Clients.*
(a)(6)	Form of Guidelines for Certification of Taxpayer Identification Number on Substitute Form W-9.*
(a)(7)	Summary Advertisement as published in The Wall Street Journal on January 9, 2006.*
(a)(8)	Press Release issued by Parent on January 9, 2006.*
(a)(9)	Press Release issued by Parent on January 3, 2006.*
(a)(10)	Analyst presentation, dated January 3, 2006.*
(a)(11)	Text of email to U.S. employees of BASF Aktiengesellschaft, dated January 3, 2006.*
(a)(12)	Transcript of Conference Call, dated January 3, 2006.*
(a)(13)	Transcript of Interview with Dr. Kurt Bock.*
(a)(14)	Press Release issued by Parent on January 24, 2006.*
(a)(15)	Press Release issued by Parent on January 27, 2006.*
(a)(16)	Press Release issued by Parent on February 6, 2006.*
(a)(17)	Transcript of Analyst Conference Call, dated February 22, 2006.*
(a)(18)	Transcript of Media Conference Call, dated February 22, 2006.*
(a)(19)	Speech by Dr. Jürgen Hambrecht, dated February 22, 2006.*
(a)(20)	Speech by Dr. Kurt Bock, dated February 22, 2006.*
(a)(21)	Analyst presentation by Dr. Jürgen Hambrecht, dated February 22, 2006.*
(a)(22)	Analyst presentation by Dr. Kurt Bock, dated February 22, 2006.*
(a)(23)	Press Release issued by Parent on February 23, 2006.*
(a)(24)	Press Release issued by Parent on March 6, 2006.*
(a)(25)	Press Release issued by Parent on March 16, 2006.*
(a)(26)	Press Release issued by Parent on April 17, 2006.*
(a)(27)	Press Release issued by Parent on April 26, 2006.*
(a)(28)	Press Release issued by Parent on May 1, 2006.*
(a)(29)	Transcript of Dr. Kurt Bock's remarks at the 1st Quarter Analyst Conference Call and Excerpt of Q&A related to Offer, dated May 4, 2006.*
(a)(30)	Interim Report, dated May 4, 2006.*
(a)(31)	Speech by Dr. Jürgen Hambrecht, dated May 4, 2006.*
(a)(32)	Amended and Restated Offer to Purchase dated May 9, 2006.*
(a)(33)	Form of Amended and Restated Letter of Transmittal.*
(a)(34)	Form of Amended and Restated Notice of Guaranteed Delivery.*
(a)(35)	Form of Amended and Restated Letter from Lehman Brothers Inc. to Brokers, Dealers, Commercial Banks, Trust Companies and Other Nominees.*
(a)(36)	Form of Amended and Restated Letter to Clients.*
(a)(37)	Investor Presentation.*
(a)(38)	Definitive Proxy Statement, dated May 12, 2006 (incorporated by reference to the Schedule 14A filed with the Securities and Exchange Commission on May 12, 2006).*
(a)(39)	Press Release issued by Parent on May 22, 2006.*
(a)(40)	Press Release issued by Parent on May 23, 2006.*
(a)(41)	Letter to Stockholders of the Company, dated May 23, 2006.*
(a)(42)	Investor Presentation, dated May 23, 2006.*
(a)(43)	Press Release issued by Parent on May 24, 2006.*
(a)(44)	Supplement to the Amended and Restated Offer to Purchase, dated May 30, 2006.*
(a)(45)	Form of Revised Letter of Transmittal.*
(a)(46)	Form of Revised Notice of Guaranteed Delivery.*

(a)(47)	Form of Revised Letter from Lehman Brothers Inc. to Brokers, Dealers, Commercial Banks, Trust Companies and Other Nominees.*
(a)(48)	Form of Revised Letter to Clients.*
(a)(49)	Press Release issued by Parent on May 30, 2006.*
(a)(50)	Press Release issued by Parent on June 6, 2006.*
(a)(51)	Press Release issued by Parent on June 9, 2006.
(b)	None.
(d)(1)	Agreement and Plan of Merger, dated May 30, 2006, among Parent, Purchaser and the Company.*
(g)	None.
(h)	None.

*

Previously filed

EX-99.(A)(51)

Exhibit (a)(51)

	June 9, 2006 P281/06e
BASF receives over 90% of Engelhard shares
•BASF Announces Completion of Subsequent Offering Period	Michael Grabicki Phone:    +49 621 60-99938 Fax:         +49 621 60-92693
	michael.grabicki@basf.com
	US media contact:
Ludwigshafen, Germany, June 9, 2006 — BASF Aktiengesellschaft (Frankfurt: BAS, NYSE: BF [ADR], LSE: BFA, SWX: AN) today announced the completion of the subsequent offering period for the outstanding shares of Engelhard.  As of 8:00 p.m. New York City time on June 8, 2006, a total of 113,489,680 shares, representing more than 90% of Engelhard’s (NYSE: EC) outstanding common stock, had been tendered into BASF’s initial tender offer and during the subsequent offering period.	Rand Pearsall
	Phone:    +1 973 245 6820
	Cell:        +1 973 626 1786
	Fax:        +1 973 245 6714 rand.pearsall@basf.com
BASF intends to complete the acquisition of Engelhard through a merger of the acquisition vehicle, Iron Acquisition Corporation, into Engelhard Corporation in which all Engelhard shares not tendered into BASF’s offer or during the subsequent offering period (other than shares held in the treasury of Engelhard or held by BASF or any of its subsidiaries) will be converted into the right to receive $39 per share.  Following the merger, Engelhard will be a wholly owned subsidiary of BASF.  Under applicable law, the merger is not subject to the approval of the remaining Engelhard stockholders.	Analysts/Investors contact:
	Christoph Beumelburg
	Phone:+1 973 245 6013
	Cell: +1 973 519 2981
	Fax: +1 973 245 6714
	christoph.beumelburg@basf.com
	BASF Aktiengesellschaf
	67056 Ludwigshafen, Germany
	Phone:+49 621 60-0
	http://www.basf.com
	Corporate Media Relations

BASF is the world’s leading chemical company: The Chemical Company. Its portfolio ranges from chemicals, plastics, performance products, agricultural products and fine chemicals to crude oil and natural gas. As a reliable partner to virtually all industries, BASF’s intelligent system solutions and high-value products help its customers to be more successful. BASF develops new technologies and uses them to open up additional market opportunities. It combines economic success with environmental protection and social responsibility, thus contributing to a better future. In 2005, BASF had approximately 81,000 employees and posted sales of more than €42.7 billion. BASF shares are traded on the stock exchanges in Frankfurt (BAS), London (BFA), New York (BF) and Zurich (AN). Further information on BASF is available on the Internet at www.basf.com.

This press release contains forward-looking statements. All statements contained in this press release that are not clearly historical in nature or that necessarily depend on future events are forward-looking, and the words “anticipate,” “believe,” “expect,” “estimate,” “plan,” and similar expressions are generally intended to identify forward-looking statements. These statements are based on current expectations, estimates and projections of BASF management and currently available information. They are not guarantees of future performance, involve certain risks and uncertainties that are difficult to predict and are based upon assumptions as to future events that may not prove to be accurate.

Many factors could cause the actual results, performance or achievements of BASF to be materially different from those that may be expressed or implied by such statements. Such factors include those discussed in BASF’s most recent Form 20-F filed with the SEC.

2

CORRESP

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June 9, 2006

BY EDGAR TRANSMISSION

Securities and Exchange Commission
Station Place, 100 F Street, N.E.
Washington, D.C. 20549

Iron Acquisition Corporation
Amendment No. 23 to Tender Offer Statement on Schedule TO

Ladies and Gentlemen:

        On behalf of Iron Acquisition Corporation, a Delaware corporation ("Purchaser"), and BASF Aktiengesellschaft, a stock corporation organized under the laws of the Federal Republic of Germany ("Parent"), transmitted herewith via the Securities and Exchange Commission's (the "Commission") EDGAR system for filing, pursuant to Regulation 14D under the Securities Exchange Act of 1934, as amended, is Amendment No. 23 (the "Amendment") to the Tender Offer Statement on Schedule TO filed with the Commission on January 9, 2006, as amended by Amendments No. 1 through 22 (as so amended, the "Statement"), by Purchaser and Parent. The Statement relates to an offer by Purchaser to purchase all the issued and outstanding shares of common stock, par value $1.00 per share, of Engelhard Corporation, a Delaware corporation (the "Company"), and the associated Series A Junior Participating Preferred Stock purchase rights issued pursuant to the Rights Agreement, dated as of October 1, 1998, between the Company and ChaseMellon Shareholder Services, L.L.C., as Rights Agent.

        A copy of this letter, together with a copy of the Amendment is being sent by overnight delivery to the Company at its principal executive office. Purchaser and Parent are also giving telephonic notice to the New York Stock Exchange of the information required by Rule 14d-6(d)(2)(i) and (ii) under the Exchange Act.

        Please direct any questions or comments to Peter Lyons at (212) 848-7666 or me at (212) 848-5486.

Very truly yours,

/s/ Lisa Toporek Lisa Toporek

Enclosure

cc: Engelhard Corporation
101 Wood Avenue
Iselin, New Jersey 08830
Attention: Mr. Barry W. Perry

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