Exhibit
10.14
[INTERNATIONAL ISOTOPES
LETTERHEAD]
December 21,
2007
Firebird Global Master
Fund II, Ltd.
c/o FG2 Advisors,
LLC
152 West 57th Street,
24th Floor
New York, New York
10019
Re:
Exercise of Class
D Warrant and Waiver of Certain Rights Therein
Ladies and
gentlemen:
This letter is being
sent to you in your capacity as holders (each a " Holder ")
of the Class D Warrants (the " Class D Warrants ") dated
March 20, 2007 issued by International Isotopes Inc. (the "
Company "). Capitalized terms used herein and not
defined have the meanings assigned to them in the Class D
Warrants.
The Company hereby
acknowledges that each of you has agreed to exercise your
respective Class D Warrant pursuant to the terms contained therein.
With respect to such exercise, the Company hereby waives the
following limitations contained in Section 11(a) of each of the
Class D Warrants: (1) that the number of shares of Common Stock
that may be acquired upon exercise of a Holder's Class D Warrant
shall be limited such that, following such exercise, the total
number of shares of Common Stock then beneficially owned by such
Holder and certain other persons, does not exce
