EXHIBIT
      4.28






$ 19,000,000




COVISA/ALCALI/COMERCIALIZADORA
      Trust




Subordinate
      Certificates




**Placement
      Agent Agreement**








March
      29,
      2005





ABN
      AMRO
      Inc.


55
      East
      52nd Street, 6th floor


New
      York,
      NY 10055





Ladies
      and Gentlemen:




1.  *Introductory* .
      Companía Vidriera, S.A. de C.V., a corporation organized under the laws of
      Mexico (“ Covisa ”),
      Industria Del Álcali, S.A. de C.V., a corporation organized under the laws of
      Mexico (“ Álcali ”),
      Comercializadora Álcali, S. de R.L. de C.V., a limited liability company
      organized under the laws of Mexico (“ Comercializadora ”),
      as
      settlers (each of Covisa, Álcali and Comercializadora, individually, a
“ Settlor ”
      and
      collectively, the “ Settlors ”),
      ABN
      AMRO Bank (Mexico), S.A., Institución de Banca Múltiple, Division Fiduciara,
      not in its individual capacity but solely as trustee (the “ Trustee ”)
      of,
      and in satisfaction of the purposes of, the Trust referred to below, and Banco
      Invex, S.A., Institución de Banca Múltiple, Invex Grupo Financiero, as common
      representative of the holders of the Preferred Certificates to be issued
      thereunder (the “ Common
      Representative ”),
      have
      entered into an Irrevocable Issuance, Administration and Payment Trust Agreement
      ( *Contrato
      de Fideicomiso Irrevocable de Emisión, Administración*  *y
      Pago* )
      dated
      as of March 23 **,** 2005
      (the
“ Trust
      Agreement ”),
      providing for the establishment of an irrevocable issuance, administration
      and
      payment trust (the “ Trust ”
      or the
“ Issuer ”).
      T he
      assets
      of th e Trust
      will include, among other things, a pool of rec eivables
      (the “ Receivables ”)
      generated from time to time by the
      Settlors and sold to the Trust pursuant
      to the Assignment Agreement ( *Contrato
      de Cesion de Dereechos al Cobro* )
      dated
      as of March
      23,
      2005 (the “ Assignment
      Agreement ”),
      among
      the Settlors and ABN AMRO Bank (Mexico), S.A. Pursuant to the Trust Agreement,
      the Trust will issue $19,000,000 principal amount of its 10.75 %
      Subordinated Certificates ( *Certificados
      Subordinados* ) (the
“ Certificates ”),
      each
      of which Certificates will constitute a Trust payment obligation backed by
      the
      Trust's ownership interest in the Receivables and the
      other assets of the Trust (the Receivables and such other assets, the
“ Trust
      Assets ”).
      The
      Certificates will be sold, o n
      a
      private placement basis pursuant to an exemption under













Section 4(2)
        of the United States Securities Act of 1933 (the “ Securities
        Act ”),
        to
        one or more “qualified institutional buyers” within the mean of Rule 144A
        under the Securities Act (each, a “ Purchaser ”
        and
        collectively, the “ Purchasers ”)
        pursuant to a Purchase Agreement to be dated as of the date of issuance of
        the
        Certificates (the “ Purchase
        Agreement ”).
        The
        Certificates are proposed to be sold to the Purchasers at the Closing Time
        referred to in Section 5.




2.  *Representations,* *Warranties
      and Agreements* .
      Each of
      the Trustee, acting to satisfy the purposes of the Trust, and the Settlors
      hereby affirms each of its representations, warranties and agreements set forth
      in the Purchase Agreement and further represents and warrants to, and agrees
      with, you as follows:




(a)  This
      Agreement has been duly authorized, executed and delivered by the Trustee,
      acting to satisfy the purposes of the Trust, and the Settlors. The execution,
      delivery and performance of the Purchase Agreement and this Agreement, and
      the
      issuance and sale of the Certificates and compliance with the terms and
      provisions thereof will not result in a breach or violation of any of the terms
      and provisions of, or constitute a default under, any statute, any rule,
      regulation or order of any governmental agency or body or any court, domestic
      or
      foreign, having jurisdiction over the Trust, the Settlors or any of their
      respective properties, or any agreement or instrument to which the Trust or
      the
      Settlors is a party or by which the Trust or any of the Settlors is bound or
      to
      which any of their respective properties is subject, or the Trust Agreement
      or
      the by-laws of the Settlors, and the Trust has full power and authority to
      authorize, issue and sell the Certificates as contemplated by the Purchase
      Agreement.




(b)  No
      consent, approval, authorization or order of, or filing with, any governmental
      agency or body or any court is required for the consummation of the transactions
      contemplated by this Agreement and the Purchase Agreement in connection with
      the
      issuance and sale of the Certificates by the Trust to the
      Purchasers.




(c)  The
      respective representations and warranties of the Trustee, acting to satisfy
      the
      purposes of the Trust, and the Settlors in the Purchase Agreement will be true
      and correct in all material respects, and the Trustee acting to satisfy the
      purposes of the Trust, and the Settlors shall have complied with all of their
      respective obligations under the Purchase Agreement in all material respects,
      as
      of the Closing Time.






(d)  The
      offer
      and sale of the Certificates by the Trust to the Purchasers in the manner
      contemplated by the Purchase Agreement will be exempt from the registration
      requirements of the Securities Act by reason of Section 4(2)
      thereof.








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3.  *Placement
      of Certificates* .
      The
      Trust hereby appoints you as its sole and exclusive placement agent in
      connection with placing the Certificates with the Purchasers. Your
      responsibility is limited to a “reasonable efforts” basis in so placing the
      Certificates, with no understanding or agreement, express or implied, on your
      part of a commitment by you to purchase or place the Certificates. You shall
      have no liability, and no obligation to purchase the Certificates, if the
      Purchasers fail to purchase the Certificates.




4.  *Payment
      of Expenses* .
      The
      Trust agrees it will pay all expenses incidental to the performance of its
      and
      the Settlors' obligations under this Agreement and the Purchase Agreement,
      including (i) all reasonable and documented fees and disbursement of
      its
      and the Settlors' counsel, (ii) all reasonable and documented expenses in
      connection with the execution, issue, authentication and initial delivery of
      the
      Certificates, the preparation of this Agreement, the Certificates, the Purchase
      Agreement and any other document relating to the issuance, offer, sale and
      delivery of the Certificates, (iii) all reasonable and documented expenses
      (including fees and disbursements of counsel) in connection with qualification
      of the Certificates for sale under the laws of such jurisdictions as you
      designate and (iv) all the reasonable and documented fees and disbursements
      of
      your counsel in an amount of up to $10,000.




5.  *Closing* .
      The
      sale of the Certificates to the Purchaser shall be held at the closing time
      determined in accordance with the Purchase Agreement (the “ Closing
      Time ”),
      which
      shall be communicated to you by fax, email or otherwise in writing. At the
      Closing Time, the Trust shall accept payment for the Certificates from the
      Purchasers (or you on behalf of the Purchasers) by official bank check or checks
      or wire transfer of federal (same day) funds and you or the Purchasers shall
      accept delivery of the Certificates in physical form.




6.
        *Indemnification*. (a) Each of the Settlors, jointly and
      severally, agrees that it will (i) indemnify and hold harmless you and your
      affiliates, and the respective directors, officers, employees and controlling
      persons of you and your affiliates from and against any direct losses, claims,
      damages or liabilities, joint or several, to which any indemnified party may
      become subject, insofar as such losses, claims, damages or liabilities (or
      actions in respect thereof) relate to, arise out of or are in connection with
      the placement of the Certificates and (ii) reimburse each indemnified party
      for
      any reasonable and documented legal or other expenses incurred by such
      indemnified party in connection with investigating or defending any such loss,
      claim, damage, liability or action as such expenses are incurred. This indemnity
      will be in addition to any liability that the Settlors may otherwise have.




(b)
        If any action, claim or demand shall be brought or alleged
      against
      an indemnified party in respect of which indemnity is to be sought against
      the
      indemnifying party under this Section 6, the indemnified party shall promptly
      notify the indemnifying party in writing, but the failure so to notify
      an




3




indemnifying
      party shall not relieve such indemnifying party from any obligation or liability
      it may otherwise have. The indemnified party shall have the right to retain
      counsel of its own choice to represent it in connection with such action, claim
      or demand, and the indemnifying party will reimburse the indemnified party
      for
      the reasonable and documented fees and expenses of such counsel as
      incurred.


(c)
           An
          indemnifying party will not, without the prior written
          consent of the indemnified parties, settle or compromise or consent to
          the entry
          of any judgment with respect to any pending or threatened action, claim
          or
          demand in respect of which indemnification may be sought hereunder (whether
          or
          nor the indemnified parties are actual or potential parties to such claim
          or
          action) unless such settlement, compromise or judgment includes an unconditional
          release of each indemnified party from all liability arising out of such
          action,
          claim or demand.
  7.  *Surviva* *l* .
        The
        respective indemnities, agreements, representations, warranties and other
        statements of the Trust, the Settlors and of you set forth in or made pursuant
        to this Agreement will remain in full force and effect, regardless of any
        investigation, or statement as to the results thereof, made by or on behalf
        of
        you, the Trust, the Settlors or any of their respective directors, officers,
        employees or controlling persons, and will survive delivery of and payment
        for
        the Certificates. If for any reason the purchase of the Certificates by the
        Purchasers is not consummated, the Trust shall remain responsible for the
        expenses to be paid or reimbursed by them pursuant to Section 4 and
        the
        obligations of the Settlors pursuant to Section 6 shall remain in
        effect.
        If the purchase of the Certificates by the Purchaser is not consummated for
        any
        reason, the Settlors will reimburse you for all out-of-pocket expenses
        reasonably incurred by you in connection with the placement of the
        Certificates.
   8.  *Notices* .
        All
        communications hereunder will be in writing and, if sent to you will be mailed,
        delivered or faxed to you at ABN
        AMRO
        Inc., 55 East 52nd Street, New York, NY 10055, 6th floor ; Facsimile:
        (212) 409-7860; Attention: Willem
        Sutherland ,
        or, if
        sent to the Trust or the Settlors, will be mailed, delivered or faxed to
        them at
        the respective addresses and fax numbers set forth under their signatures
        to
        this Agreement.
   9.  *Successors* .
        This
        Agreement will inure to the benefit of and be binding upon the parties hereto
        and their respective successors and the controlling persons referred to in
        Section 6, and no other person will have any right or obligation
        hereunder.
   10.  *Counterparts* .
        This
        Agreement may be executed in any number of counterparts, each of which shall
        be
        deemed to be an original, but all such counterparts shall together constitute
        one and the same Agreement.
   4
  **11.**  ***Applicable
          Law*** **.
          This Agreement shall be governed by, and construed in accordance with,
          the laws
          of the State of New York without regard to principles of conflicts of
          laws.**
  
 Each
          party hereby submits to the non-exclusive jurisdiction of the Federal and
          state
          courts in the Borough of Manhattan in The City of New York in any suit
          or
          proceeding arising out of or relating to this Agreement or the transactions
          contemplated hereby. Each of the Trust and the Settlors irrevocably appoints CT
          Corporation System at 111 Eighth Avenue, New York, New York
          10011 ,
          as its
          authorized agent in the Borough of Manhattan in The City of New York upon
          which
          process may be served in any such suit or proceeding, and agrees that service
          of
          process upon such agent, and written notice of said service to the Trust
          or the
          Settlors, by the person serving the same to the address provided in
          Section 8, shall be deemed in every respect effective service of
          process
          upon such party in any such suit or proceeding.
  12.  *Limitation
          of Liabilities* . It is
          expressly understood and agreed by the parties hereto that (a) this
          Agreement is executed and delivered by ABN AMRO Bank (Mexico) S.A.
          not
          individually or personally but solely as Trustee acting to satisfy the
          purposes
          of the Trust, in the exercise of the power and authority conferred and
          vested in
          it, (b) each of the representations, undertakings and agreements
          herein
          made on the part of the Trustee is made and intended not as a personal
          representation, undertaking or agreement by ABN AMRO Bank (Mexico) S.A.
          but
          is made in satisfaction of the purposes of the Trust and intended for the
          purpose of binding only the Trust and (c) under no circumstances
          shall ABN
          AMRO Bank (Mexico) S.A. be personally liable for the payment of
          any
          indebtedness or expenses of the Trust
   If
          the
          foregoing is in accordance with your understanding of our agreement, kindly
          sign
          and return to the each of the Trust and the Settlors one of the counterparts
          hereof, whereupon it will become a binding agreement among the Trust, the
          Settlors and you in accordance with its terms.
   Very
                    truly yours,ABN
                    AMRO BANK (MEXICO) S.A., AS
                  TRUSTEE,
                    ACTING TO SATISFY THE
                  PURPOSES
                    OF THE TRUST,byName:Title:Address
                    and Fax Number for Notices:
                  
                  ABN
                    AMRO Bank (México), S.A.
                  Institución
                    de Banca Múltiple,
                  División
                    Fiduciaria
                  Avenida
                    Paseo de la Reforma No. 600-320
                  México,
                    D.F. 01210
                  Phone:
                    5257-7810
                  Facsimile:
                    5257-7829
                  Attention:
                    División Fiduciaria
 5






COMPAÑÍA
                    VIDRIERA, S.A. DE C.V.,By
                ByName:Claudio
                    del Valle
                  Title:Attorney-in-Fact
                
                Name:Álvaro
                    Rodríguez
                  Title:Attorney-in-FactAddress
                      and Fax Number for Notices:
                  Ricardo
                    Margain No. 440
                  Colonia
                    Valle del Campestre
                  San
                    Pedro Garza García, NL 66265, México
                  Fax:
                    +52 81 8863 1290
 
 
 
 INDUSTRIA
                    DEL ÁLCALI, S.A. DE C.V.,By
                ByName:Claudio
                    del Valle
                  Title:Attorney-in-Fact
                
                Name:Álvaro
                    Rodríguez
                  Title:Attorney-in-FactAddress
                    and Fax Number for Notices:
                  Ricardo
                    Margain No. 440
                  Colonia
                    Valle del Campestre
                  San
                    Pedro Garza García, NL 66265, México
                  Fax:
                    +52 81 8863 1290
 
 
 COMERCIALIZADORA
                    ÁLCALI, S. DE R.L. DE C.V.,By
                ByName:Claudio
                    del Valle
                  Title:Attorney-in-Fact
                
                Name:Álvaro
                    Rodríguez
                  Title:Attorney-in-FactAddress
                    and Fax Number for Notices:
                  Ricardo
                    Margain No. 440
                  Colonia
                    Valle del Campestre
                  San
                    Pedro Garza García, NL 66265, México
                  Fax:
                    +52 81 8863 1290
    6
  The
          foregoing Placement Agent Agreement
 is
          hereby
          confirmed and accepted as of the
 date
          first above written.
 
 ABN
          AMRO
          Inc.,
 
 
 By__________________________________
 Willem
          Sutherland
 [Title]
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