MEMC ELECTRONIC MATERIALS, INC.
                             STOCK OPTION AGREEMENT
                                     (Date)

(Name)
(Address)
(Address)

     This letter describes the terms of the grant by MEMC Electronic  Materials,
Inc. (the  "Company") to you of  nonqualified  stock options (the  "Options") to
purchase  shares of the Company's  Common  Stock,  par value $.01 per share (the
"Common  Stock"),  under the Company's 1995 Equity  Incentive Plan (the "Plan").
The Company is granting  these  Options to you in  recognition  of your valuable
services to the Company and to facilitate  your  participation  in the Company's
success.

     Capitalized  terms used in this letter  without  definition  shall have the
meanings  assigned to them in the Plan. This letter,  the Options and the Common
Stock issued upon the exercise of the Options  shall be  controlled by the terms
of the Plan, the terms of which are  incorporated by reference into this letter.
In the event of any conflict or inconsistency  between the Plan and this letter,
the Plan will govern.

     Before we describe how the Options work, it is important that you know that
none of the Options may be sold,  transferred,  assigned,  pledged, or otherwise
encumbered  or  disposed  of,  except  by  will  or  the  laws  of  descent  and
distribution.  Therefore,  during your lifetime,  an Option shall be exercisable
only  by you  or by  your  guardian  or  legal  representative.  Each  permitted
transferee of an Option shall, as a condition of the transfer  thereof,  execute
an  agreement  pursuant to which it shall agree to comply with the terms of this
letter.

     1. Grant of Options.  You are hereby granted the number of Options shown on
Exhibit A, attached to this letter. Although you are first receiving this letter
today,  these Options became  effective as of  __________,  the "Date of Grant."
Each such Option  will  entitle you to  purchase  upon  payment of the  Exercise
Price,  one share of Common  Stock.  The decision to use an Option to purchase a
share of Common  Stock will be  referred  to in this  letter as  "exercising  an
option." The "Exercise  Price" shall be the amount shown on Exhibit A, which was
the Fair Market  Value,  as defined in the Plan,  of a share of Common  Stock on
__________.

     The Options granted  pursuant to this letter shall be  non-qualified  stock
options, which are not qualified under Section 422 of the Code.

     2. Terms and Conditions of Options.  The Options  granted under this letter
have the following terms and conditions:

          (a)  Vesting.  Of the total  number of Options  granted to you by this
     letter,  you will have the right to  exercise  25% of them  (i.e.  25% will
     vest) on the first  anniversary  of the Date of Grant and an additional 25%
     on each  anniversary  of the Date of  Grant  thereafter,  such  that by the
     fourth  anniversary  of the  Date of  Grant,  you will  have  the  right to
     exercise  all (100%) of them  (i.e.  100% will be  vested).  If a Change in
     Control  occurs  (except  as the  Compensation  Committee  of the  Board of
     Directors  of the Company (the  "Committee"),  as  constituted  immediately
     prior to such  Change  in  Control,  may  otherwise  determine  in its sole
     discretion)  any Options then  outstanding  (other than any Option  granted
     within six months of such Change in Control) will become fully  exercisable
     as of the date of the Change in Control.

          (b) Option Period. The Options will not be exercisable after the tenth
     anniversary of the Date of Grant, and may be subject to earlier termination
     as described below and in the Plan.

          Upon   termination  of  your  employment  with  the  Company  and  its
     Subsidiaries  for reasons  other than your death,  Disability or Retirement
     you (or your estate) may exercise any Option to the extent  exercisable  on
     the  date  of  termination  within  the  sixty  day  period  after  such  a
     termination  of employment  (but never later than the tenth  anniversary of
     the Date of Grant).  Any  Options  which have not yet vested at the time of
     termination of your employment shall terminate and be cancelled  (except as
     the Committee may otherwise  determine in its sole  discretion).  Also, any
     Options  not  exercised  within  sixty  days after  such a  termination  of
     employment shall terminate and be cancelled.

          Upon   termination  of  your  employment  with  the  Company  and  its
     Subsidiaries  on account  of your  death,  Disability  or  Retirement,  all
     Options  shall vest and you (or your  Beneficiary)  may exercise any or all
     Options within the three year period after such a termination of employment
     (but  never  later  than  the  tenth  anniversary  of the  Date of  Grant);
     provided, however, that in the event of Disability or Retirement, no Option
     may be exercised  until at least six months  after its Date of Grant.  From
     time to time, on a form  acceptable  to the Committee or its delegate,  you
     may  designate  any  person  or  persons  (concurrently,   contingently  or
     successively)  to whom the Options shall be  transferred  in the event that
     you die before you exercise the Options.  A  beneficiary  designation  form
     shall be effective only when the form is signed by you and filed in writing
     with the  Company  while you are alive,  and shall  cancel all  beneficiary
     designation  forms that you previously  signed and filed. If no Beneficiary
     is so designated, your Beneficiary shall be your estate or the distributees
     thereof.

          For  purposes  of  this   paragraph,   "Retirement"   shall  mean  the
     termination of your employment with the Company after you attain sixty-five
     years of age,  or after you attain  fifty-five  years of age and the sum of
     your age and years of Vesting  Service  as  defined in the MEMC  Electronic
     Materials,  Inc.  Pension  Plan for  Salaried  Employees is at least eighty
     (80).

          Notwithstanding  anything to the contrary in this letter, in the event
     of your termination of employment with the Company and its Subsidiaries for
     Cause (as defined  below),  all  Options,  whether or not vested,  shall be
     cancelled and no longer exercisable as of the date of such termination.

               Termination for "Cause" shall mean termination of your employment
          because of:

                    (i) any act or omission that  constitutes a material  breach
               of any of the material  obligations of any  employment  agreement
               that you may have  with the  Company  or any of its  Subsidiaries
               (other than by reason of your death or Disability;

                    (ii) the continued  failure or refusal of you to perform the
               material  duties required of you as an employee of the Company or
               any of its  Subsidiaries  (other  than by reason of your death or
               Disability);

                    (iii) any willful  material  violation  by you of any law or
               regulation  applicable  to the  business of the Company or any of
               its Subsidiaries,  or your conviction of a felony, or any willful
               perpetration by you of a common law fraud; or

                    (iv) any other willful misconduct by you which is materially
               injurious to the financial  condition or business  reputation of,
               or is otherwise  materially  injurious  to, the Company or any of
               its Subsidiaries.

          (c) Exercising Options.  You may exercise any or all vested Options by
     notifying the Company in writing that you wish to exercise your Options and
     accompanying  the written  notice (as  described in paragraph 4 below) with
     the  payment for the Common  Stock you are  purchasing  with such  Options.
     Payment  must be equal to the  total  number  of  Options  that you wish to
     exercise, multiplied by the Exercise Price.

          Payment may be made in cash,  certified  or bank check,  note or other
     instrument acceptable to the Committee. Payment may also be made in full or
     in part in shares of Common Stock with a Fair Market Value  (determined  as
     of the date of exercise  of such Stock  Option) at least equal to such full
     or partial  payment.  Common  Stock used to pay the  Exercise  Price may be
     shares that you already own, or the Company may  withhold  shares of Common
     Stock that you would  otherwise  have  received  upon exercise of the Stock
     Option. You also may exercise a Stock Option through a "cashless  exercise"
     procedure involving a broker or dealer approved by the Committee,  provided
     that the conditions described in Section 8(f) of the Plan are satisfied.

          If you are subject to Section 16 of the  Exchange  Act, you shall have
     the unfettered  right (but not the obligation) to pay the exercise price in
     full or in part in shares of Common Stock in  accordance  with Section 8(i)
     of the Plan.

          The date of  exercise  will be the date  that all of the  requirements
     above, as well as the  requirements in 2(e) below,  are met. No certificate
     showing the Common Stock  purchased under such Option will be issued to you
     under 2(f) below until all of these requirements are met.

          (d) Shareholder  Rights. You will have no rights as a shareholder with
     respect to any shares of Common  Stock  purchased  upon the  exercise of an
     Option until a certificate or certificates for such shares is issued to you
     making you the "holder of record" of such shares. Other than under Sections
     13(b) and 13(c) of the Plan,  no  adjustment  will be made for dividends or
     distributions  or other  rights  related to any share for which the date of
     such dividend or distribution is prior to the date on which you will become
     the holder of record of the shares.

          (e) Limitation on Exercise.  Notwithstanding  the other  provisions of
     this  letter,  an Option  shall not be  exercisable  unless and until (i) a
     registration  statement  under the Securities Act of 1933, as amended,  has
     been duly filed and  declared  effective  pertaining  to the  Common  Stock
     subject to such Option and such Common Stock will have been qualified under
     applicable  state  "blue  sky"  laws,  or (ii)  the  Committee  in its sole
     discretion  determines that such registration,  qualification and status is
     not  required as a result of the  availability  of an  exemption  from such
     registration, qualification, and status under such laws.

          (f) Issuance of  Certificate.  As soon as  practicable  following  the
     exercise  of any  Options,  subject to the tax  withholding  provisions  of
     Section  3(b), a  certificate  showing the number of shares of Common Stock
     issued in connection with such exercise will be issued in your name.

     3. Miscellaneous.

          (a) No Rights to Grants or Continued Employment. You will not have any
     claim or right to receive future grants under the Plan. Nothing in the Plan
     or in this letter will give you any right to continued  employment with the
     Company or any Subsidiary, as the case may be, or interfere in any way with
     the right of the Company or a Subsidiary  to terminate  your  employment at
     any time, with or without cause.

          (b) Tax  Withholding.  If the Company is  required  by any  government
     entity to  withhold  an amount  from your wages as a result of any grant or
     exercise  of Options  pursuant  to this  letter,  the  Company  will not be
     required to deliver a stock certificate to you until you pay to the Company
     the amount  required  to be withheld  from your wages with  respect to such
     event.  Payment  of such  amount  may be in cash,  withholding  from  other
     compensation or in shares of Common Stock with a Fair Market Value equal to
     such payment. Common Stock used to pay the withholding amount may be shares
     that you already  own, or shares of Common  Stock that you would  otherwise
     have received upon the exercise of the Option.

          If you are subject to Section 16 of the  Exchange  Act, you shall have
     the  unfettered  right but not the  obligation  to direct  and  compel  the
     Company to withhold, or to accept from you, such number of shares of Common
     Stock  as is  necessary  to pay in whole or in part  your  withholding  tax
     obligation, in accordance with Section 16(a)(i) of the Plan.

          (c) No  Restriction on Right of Company to Effect  Corporate  Changes.
     Neither  the Plan nor this  letter  will  affect or restrict in any way the
     right or power of the Company or its  shareholders to make or authorize any
     corporate changes described in Section 13 of the Plan.

     4. Notices. All notices and other  communications  discussed in this letter
will be in writing and will be delivered by hand or sent by mail  addressed,  if
to you, to your attention at the mailing address that you will have specified to
the Company in writing  and, if to the Company,  to it at 501 Pearl  Drive,  St.
Peters,  Missouri 63376,  Attention:  Chief Financial Officer.  All such notices
will be  conclusively  deemed to be received and will be  effective,  if sent by
hand delivery,  upon receipt, or if sent by registered or certified mail, on the
fifth day after the day on which such notice is mailed.

     5. Entire  Letter;  Governing  Law. This letter and the Plan  represent the
entire  understanding  between  you and the  Company  and  supersede  all  prior
understandings  relating to the subject matter of this letter.  This letter will
be governed  by, and  construed  in  accordance  with,  the laws of the State of
Delaware without giving effect to conflicts of law principles.

                                MEMC Electronic Materials, Inc.

                                By: ___________________________________________
                                          Huston E. Sherrill
                                Title: Corporate Vice President, Human Resources



                                    Exhibit A

           MEMC Electronic Materials, Inc. 1995 Equity Incentive Plan
                       Stock Option Award Letter Agreement
                                     (Date)



Participant Name:

Number of Options:

Exercise Price: