Agreement

between

Helmut Swyen
Am Oberen Feld 105, 40668 Meerbusch
("Seller 1")

Herbert Hegener
Sebastiansweg 20, 40231 Dusseldorf
("Seller 2")


Des-Dur Vermogensverwaltungs GmbH, Hallbergmoos
AG Munchen HRB 120192
duly represented by its managing director Dr. Andreas Rodin
("Purchaser")


Isonics Corporation
4010 Moorpark Avenue, Suite 119
San Jose, CA 95117, U.S.A.
duly represented by its managing director Jim Alexander.


WHEREAS,  the  parties  hereto  have  entered  on May 29,  1998  into a sale and
purchase  agreement  relating to all shares in the  registered  share capital of
Chemotrade  Chemiehandelsgesellschaft  mbH, Dusseldorf ("Chemotrade"),  notarial
deed no. 28/1998 of the notary-public Wilhelm Hebing, Berlin;

WHEREAS, the Purchaser has purchased from the Seller 1 and the Seller 2, and the
Seller 1 and the  Seller 2 have  sold to the  Purchaser,  all  their  Chemotrade
shares under said notarial deed;




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WHEREAS, the Chemotrade shares shall be assigned on the Closing Date (as defined
in the sale and  purchase  agreement)  by the  Seller 1 and the  Seller 2 to the
Purchaser  against (i) payment of DM 1.5 million plus interest thereon at a rate
of 10% p.a. from July 1, 1998 until the Closing Date to each of the Seller 1 and
the Seller 2 (in aggregate DM 3 million),  and (ii)  delivery of 178,865  common
shares  of  Isonics  Corporation  to each of the  Seller 1 and the  Seller 2 (in
aggregate 357,730 common shares);

WHEREAS,  Chemotrade  has an  account  payable to  Isonics  Corporation  of US-$
924,000 and has an account receivable in the amount of US-Dollar 1,018,500;

WHEREAS,  the parties hereto intend to modify the sale and purchase agreement in
respect of the obligations to be satisfied by the Purchaser on the Closing date;

Now, therefore, the parties hereto agree as follows:

1.       Isonics  Corporation  hereby  assigns  to  the  Purchaser  its  account
         receivable  from  Chemotrade  in the  amount  of  US-$924,000  and  the
         Purchaser  hereby accepts such  assignment.  Isonics  Corporation  will
         account  for  such  assignment  as  an  investment  in  the  Purchaser.
         Chemotrade hereby confirms the assignment. Isonics Corporation confirms
         that  it has not  otherwise  disposed  of its  account  receivable  and
         represents  and  warrants  that such  assignment  does not  violate any
         arrangement, agreement or undertaking of Isonics Corporation.


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2.       Chemotrade  hereby  pledges and assigns by way of security  its account
         receivable  in  the  amount  of   US-$1,018,500  to  the  Purchaser  as
         collateral  for  Chemotrade's  account  payable to the Purchaser in the
         amount of US-$924,000.

3.       The Purchaser hereby assigns its account  receivable from Chemotrade in
         the amount of  US-$1,018,500  in two equal  instalments  of US-$462,000
         each to the Seller 1 and the Seller 2 and the Seller 1 and the Seller 2
         hereby accept such  assignment.  Chemotrade  confirms the assignment by
         the Purchaser to the Seller 1 and the Seller 2 and undertakes in favour
         of the  Seller  1 and  the  Seller  2 not  to  dispose  of its  account
         receivable up to the amount of US-$1,018,500  other than in fulfilment/
         satisfaction  of the  account  payable  in the  amount  of  US-$924,000
         assigned by the Purchaser to the Seller 1 and the Seller 2.

4.       The  Purchaser  and the  Seller 1 and the  Seller  2 agree  that on the
         Closing  Date the  Chemotrade  shares shall be assigned by the Seller 1
         and the Seller 2 to the  Purchaser  against  (i) a cash  payment by the
         Purchaser to the Seller 1 and the Seller 2 in the  aggregate  amount of
         DM  1,336,800  plus  interest  thereon  a rate of 10% from July 1, 1998
         until the  Closing  Date,  (ii)  delivery by the  Purchaser  of 178,865
         common  shares of Isonics  Corporation  to each of the Seller 1 and the
         Seller 2, and (iii) an  undertaking  of the  Purchaser in favour of the
         Seller 1 and the Seller 2 to pay  interest  on the  account  receivable
         from  Chemotrade in the amount of US-$924,000 at a rate of 2% per month
         from July 1, 1998 through the date of receipt of the account receivable
         by the Seller 1 and the Seller 2.

5.       Isonics Corporation  guarantees all obligations undertaken hereunder by
         the Purchaser.  This Agreement and the  assignments  and the pledge set
         forth herein shall be governed by German law.

Dusseldorf, July 15, 1998




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Herbert Hegener                                               Helmut Swyen



Berlin, July 16, 1998


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Des-Dur Vermogensverwaltungsgesellschaft GmbH
Dr. Andreas Rodin


San Jose, July 16, 1998


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Isonics Corporation
Jim Alexander