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                                                                 EXHIBIT 10-YYY


October 1, 1998


To:      Marcel Coinne

                   INTERNATIONAL TRANSFER LETTER OF AGREEMENT

The MEMC  International  Transfer Policy ("Policy") applies to all international
transfers.  This letter of agreement will record our mutual understanding of the
current provisions of the Policy, as they apply specifically and individually to
you in your international transfer. This Letter of Agreement does not constitute
or create an employment  contract and does not replace the basic MEMC employment
contract.

This  agreement  supercedes  in its entirety all previous  agreements  with MEMC
Electronic Materials, Inc. and its affiliates, including but not limited to Huls
Benelux S.A. except as noted herein.

You are  currently  on  assignment  from Huls  Benelux  S.A. to MEMC  Electronic
Materials,  Inc. in the U.S. Your payroll  administration is handled by the Huls
Benelux  location.  This  location  will  close,  and as a  result  you  will be
indefinitely  transferred  from the Huls Benelux  payroll to the MEMC Electronic
Materials,  Inc. payroll in the U.S. The effective date of this transfer will be
October 1, 1998.

On this  transfer your initial  position  will be to continue as Corporate  Vice
President  Customer  Operations in St.  Peters,  Missouri as an employee of MEMC
Electronic Materials, Inc.

This letter outlines the total consideration for services to be performed.

1.   Compensation

     Your base salary initially will be $230,000 per year, reduced by the amount
     of contribution toward life insurance coverage, disability coverage and the
     pension plan that you would have paid under the Huls  Benelux  arrangement.
     The base salary will be based on and administered  under the salary plan of
     MEMC Electronic Materials,  Inc. Reviews of base salary will occur in a way
     similar to that you have experienced previously.

     You will also be eligible to participate in the MEMC Electronic  Materials,
     Inc. Annual Incentive Plan and Long-Term Incentive Plan.

     As a one-time  adjustment,  MEMC will pay you $115,000 either as a lump sum
     or in two (2)  installment  payments,  six months apart.  The first payment
     will  be made on  October  15,  1998 as a  separate  check,  provided  this
     Agreement  has  been  signed.  This  payment  will  not be  considered  for
     pensionable earnings.

2.   Medical and Dental Coverage

     You will be  covered by the MEMC  Medical  Plan and the MEMC  Dental  Plan,
     provided you make the necessary contributions. As a U.S. employee, you will
     now be eligible to contribute  on a pre-tax basis if you wish.  Pam Barnes,
     Benefit Representative, will explain this to you.

     Upon  retirement,  you will be eligible for coverage under the MEMC Retiree
     Medical Plan, as it is then provided to employees with like service.

     MEMC will not pay Belgian social contributions,  nor will coverage with DKV
     be continued. You may, however, continue that coverage if you wish, at your
     own expense.

3.   Life Insurance and Disability Coverage

     You will continue to be covered under the Royale Belge contracts, currently
     owned and  administered by Huls Benelux.  These contracts will be converted
     to an individual  policy for you, with coverage similar to that provided by
     Huls Benelux,  owned by MEMC Electronic  Materials,  Inc. Premiums for life
     insurance coverages paid by MEMC on your behalf may be considered wages for
     purposes  of U.S.  income tax.  Accordingly,  this will be reported on your
     Form W-2.

     No coverages  will be provided to you under the MEMC Life Insurance Plan or
     MEMC Disability Plan.

4.   Pension

     MEMC  Electronic  Materials,  Inc.  agrees to  continue  providing  pension
     coverage for you under the contract with Royal Belge.  The premium payments
     made by MEMC on your behalf will be considered  taxable income for you, and
     as such, will be included on your Form W-2 each year.

     MEMC will also continue to provide the MEMC Electronic Materials,  Inc. TCN
     Retirement Plan.  Except as otherwise  provided here, this agreement in the
     form provided to you since 1989 as an  attachment to your prior  employment
     agreements will continue without change.  MEMC agrees,  however, to provide
     the TCN  Supplement as either an annuity or in one lump-sum,  calculated as
     the  actuarial  present  value  of  the  annuity  benefit,   based  on  the
     
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     assumptions within the TCN Retirement Plan.

     All years of service with  Monsanto,  Huls and MEMC will be considered  for
     pension purposes.

     You will not be eligible for the MEMC Pension Plan,  the MEMC  Supplemental
     Pension Plan, or the MEMC Retirement Savings Plan.

5.   Vacation

     You will continue to be eligible for six (6) weeks vacation based upon your
     initial MEMC hire date.

6.   Travel Grants

     You will be entitled to receive one travel grant of a  round-trip  business
     class airfare to the country of origin for yourself and your spouse in each
     of three  years out of five  after  your  transfer.  There  will be no cash
     payment in lieu of travel.

     You may use the travel  grant any way you wish:  travel to place of origin,
     visits by relatives to the location of assignment  or vacation  travel to a
     location  other  than the point of  origin.  You will also be  entitled  to
     emergency  travel  grants  for  special  circumstances  such  as  death  in
     immediate family, serious illness, etc., for a period of five years.

7.   Income Tax Preparation Service

     Considering your long duration out of Belgium,  you will have no tax filing
     obligation  there. To ensure your tax  equalization  obligation you will be
     expected to continue to be tax equalized  through  September  1998. The tax
     equalization  settlement  process,  based on the year 1998,  will  continue
     during the coming year 1999 and beyond,  if required.  Any costs associated
     with tax equalization services will not result in taxable income to you.

     With the international  transfer, tax preparation services will continue to
     be provided  for you. The cost of such  services  will be borne by MEMC and
     will be provided for an indefinite period of time during your assignment in
     the U.S., plus one additional year after you return to Europe.  The cost of
     such services will be taxable income for you.

     Please  contact the tax  consultants to inform them of your transfer to the
     U.S.

8.   Other Services

     MEMC agrees to provide reasonable  services such as those provided by Akin,
     Gump attorneys and KPMG for estate planning,  tax planning and other normal
     executive  services for your personal use. The cost for these services will
     be taxable income to you.

     Any services provided to MEMC as required for administrative, accounting or
     tax  purposes  will be paid by MEMC  and will not be  included  as  taxable
     income to you.


9.   Home Loan

     At the time that you were initially  transferred to the U.S., MEMC provided
     a home loan of $50,000. You will repay that $50,000 when you sell the home,
     or if you become  employed  by another  employer  in the U.S.  MEMC will no
     longer  contribute  toward the monthly  mortgage  on the home,  and you may
     retain any increase in value  realized at the time of the sale of the home,
     over and above the $50,000 that was loaned to you. There will be no taxable
     income to you as a result of this loan, so long as the loan is secured with
     a Second Deed of Trust.

10.  Automobile

     You may purchase your current  automobile at a cost of $1,000.  This amount
     will be  deducted  from other  payments  due you on October 15,  1998.  The
     Company  will  have  no  further  obligation  to you  with  regard  to your
     automobile.

11.  Termination

     If you are terminated without cause, MEMC Electronic Materials, Inc. agrees
     to provide you with a lump sum  payment  equal to two weeks of pay for each
     year of service  plus one  additional  week of pay.  This  payment  will be
     subject to normal withholding taxes.

12.  Death

     Should you or your  spouse die in the  country of  employment,  the Company
     will pay the cost of  preparing  and  shipping  the  remains  to Europe for
     burial and for immediate  family funeral travel.  The Company will also pay
     all expenses  involved in relocation  of your spouse back to Europe.  These
     terms  will  normally  apply for a period  of 5 years  from the date of the
     transfer. The cost of these services will be taxable income to you.

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13.  Repatriation

     At the time of your  termination or  retirement,  the Company will move you
     and your spouse back to Europe  within a reasonable  time,  not to exceed 6
     months, after termination.  After the move, we agree to provide warehousing
     of your household  goods for some  reasonable  time period while you find a
     place  to  live.  The cost of these  services  will be  grossed-up  for tax
     purposes.

     The company  will assume no  relocation  obligation  if you are employed by
     another company.

If you are in agreement with the provisions  outlined above and those  contained
in the policy,  will you please date, sign, and return the original copy of this
letter to Peggy Stonum, retaining a copy for your files.

Best wishes to you on your new permanent transfer.


/s/ Klaus R. von Horde                      09/30/98
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Klause R. von Horde                                  Date
President and COO, MEMC, Inc.


/s/ Margaret B. Stonum                      09/30/98
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Margaret B. Stonum                                   Date
Director, Compensation & Benefits
Human Resources



Accepted:

/s/ Marcel Coinn                            09/30/98
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Marcel Coinne                                        Date