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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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MIC-Info: RSA-MD5,RSA,
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<SEC-DOCUMENT>0000716039-05-000113.txt : 20050812
<SEC-HEADER>0000716039-05-000113.hdr.sgml : 20050812
<ACCEPTANCE-DATETIME>20050812175727
ACCESSION NUMBER:		0000716039-05-000113
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20050810
FILED AS OF DATE:		20050812
DATE AS OF CHANGE:		20050812

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			UNOCAL CORP
		CENTRAL INDEX KEY:			0000716039
		STANDARD INDUSTRIAL CLASSIFICATION:	CRUDE PETROLEUM & NATURAL GAS [1311]
		IRS NUMBER:				953825062
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			0901

	BUSINESS ADDRESS:	
		STREET 1:		2141 ROSECRANS AVE
		STREET 2:		STE 4000
		CITY:			EL SEGUNDO
		STATE:			CA
		ZIP:			90245
		BUSINESS PHONE:		3107267600

	MAIL ADDRESS:	
		STREET 1:		2141 ROSECRANS AVE
		STREET 2:		STE 4000
		CITY:			EL SEGUNDO
		STATE:			CA
		ZIP:			90245

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			MCCLEAN FERRELL P
		CENTRAL INDEX KEY:			0001168551

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-08483
		FILM NUMBER:		051022971

	BUSINESS ADDRESS:	
		STREET 1:		C/O GRAFTECH INTERNATIONAL LTD.
		STREET 2:		1521 CONCORD PIKE, SUITE 301
		CITY:			WILMINGTON
		STATE:			DE
		ZIP:			19803
		BUSINESS PHONE:		3027788227

	MAIL ADDRESS:	
		STREET 1:		GRAFTECH INTERNATIONAL LTD.
		STREET 2:		1521 CONCORD PIKE, SUITE 301
		CITY:			WILMINGTON
		STATE:			DE
		ZIP:			19803
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>f4formccl.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2005-08-10</periodOfReport>

    <notSubjectToSection16>1</notSubjectToSection16>

    <issuer>
        <issuerCik>0000716039</issuerCik>
        <issuerName>UNOCAL CORP</issuerName>
        <issuerTradingSymbol>UCL</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001168551</rptOwnerCik>
            <rptOwnerName>MCCLEAN FERRELL P</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O UNOCAL CORPORATION</rptOwnerStreet1>
            <rptOwnerStreet2>2141 ROSECRANS AVE, SUITE 4000</rptOwnerStreet2>
            <rptOwnerCity>EL SEGUNDO</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>90245</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock / $1.00 Par Value</value>
                <footnoteId id="F1"/>
            </securityTitle>
            <transactionDate>
                <value>2005-08-10</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>116.2406</value>
                    <footnoteId id="F2"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>61.9405</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>6173.1426</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock / $1.00 Par Value</value>
                <footnoteId id="F1"/>
            </securityTitle>
            <transactionDate>
                <value>2005-08-10</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>D</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>6173.1426</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F3"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Stock Option / (Right to Buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>30.385</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2005-08-10</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>D</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>8188.</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F4"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F5"/>
            </exerciseDate>
            <expirationDate>
                <value>2012-12-03</value>
                <footnoteId id="F4"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock / $1.00 Par Value</value>
                    <footnoteId id="F1"/>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>8188.</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
        <derivativeTransaction>
            <securityTitle>
                <value>Stock Option / (Right to Buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>27.615</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2005-08-10</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>D</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>3003.</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F4"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F6"/>
            </exerciseDate>
            <expirationDate>
                <value>2013-05-01</value>
                <footnoteId id="F4"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock / $1.00 Par Value</value>
                    <footnoteId id="F1"/>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>3003.</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Pursuant to the Agreement and Plan of Merger among Unocal Corporation, Chevron Corporation and Blue Merger Sub Inc. (the &quot;Merger Agreement&quot;), each share of Unocal Corporation Common Stock issued and outstanding immediately prior to the effectiveness of the merger on August 10, 2005 (the &quot;Merger&quot;), together with the Preferred Stock Purchase Rights attached thereto, was converted into the right to receive the merger consideration specified in the Merger Agreement.</footnote>
        <footnote id="F2">Stock Units credited for voluntary deferral of director
fees under the 2004 Directors' Deferred Compensation and
Restricted Stock Unit Award Plan (the &quot;Directors' Plan&quot;).</footnote>
        <footnote id="F3">In connection with the Merger, the reporting person is entitled to receive merger consideration in both cash and/or stock of Chevron Corporation for Unocal stock owned, subject to election and proration. Based on a press release issued by Chevron on August 10, 2005 announcing preliminary results of elections for merger consideration, and valuing Chevron shares at the closing price of $62.48 on August 10, 2005, the estimated value of the merger consideration to be received by the reporting person in exchange for the 500 Unocal shares owned by the reporting person is between $32,177 and $33,737, depending upon the election made and the final election and proration results. In connection with the Merger, each of the 5,673.1426 Director Units owned by the reporting person under the Directors' Plan was converted into Chevron Shares at the ratio of 1.068831 Chevron shares for each Unocal Stock Unit.</footnote>
        <footnote id="F4">This option was assumed by Chevron Corporation pursuant to the Merger Agreement, and converted into an option to purchase a revised number of Chevron Corporation common shares (determined by multiplying the number of shares of Unocal Common Stock subject to the option by the Stock Award Exchange Ratio, rounded down to the nearest whole share) at a new exercise price (determined by dividing the exercise price per share of Unocal Common Stock subject to the option by the Stock Award Exchange Ratio, rounded up to the nearest one hundredth of a cent).  The Stock Award Exchange Ratio is 1.0688331.  The new option expiration date is changed to 8-10-2008.</footnote>
        <footnote id="F5">The option was scheduled to become vested in three equal installments on 12-3-2003,
12-3-2004 and 12/3/2005.  The option became fully vested upon the effectiveness of the merger on August 10, 2005.</footnote>
        <footnote id="F6">The option became 50% exercisable on May 1, 2004 and 50%
exercisable on May 1, 2005.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Paul R. Moore, Asst Secretary, Attorney-In-Fact</signatureName>
        <signatureDate>2005-08-12</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
-----END PRIVACY-ENHANCED MESSAGE-----