SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the

Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): December 28, 2022

INTERNATIONAL ISOTOPES INC.

(Exact Name of Registrant as Specified in Its Charter)

208-524-5300

(Registrant’s Telephone Number, Including Area Code)

N/A

(Former Name or Former Address, if Changed Since Last Report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

o Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

o Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

o Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

o Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act: None

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§ 230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§ 240.12b-2 of this chapter).

Emerging growth company  o

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act.  o

The information set forth in Item 5.03 of this Current Report on Form 8-K is incorporated by reference into this Item 3.03.

On December 21, 2022, International Isotopes, Inc. (the “Company”) received approval of a further modification to the maturity date of its Series C Convertible Redeemable Preferred Stock (the “Series C Preferred Stock”) from a majority of the outstanding shares of the Series C Preferred Stock. The modification extends the maturity date of the Series C Preferred for an additional two years to February 28, 2025. All other terms in the Series C Preferred Stock remain unchanged. In connection therewith, on December 28, 2022, the Company filed a Certificate of Amendment to Statement of Designation of the Series C Preferred Stock (the “Certificate of Amendment”) with the Secretary of State of the State of Texas to reflect the approved modification.

The foregoing description of the Certificate of Amendment does not purport to be complete and is subject to, and is qualified in its entirety by reference to, the full text of the Certificate of Amendment, which is attached as Exhibit 3.1 to this Current Report on Form 8-K, and is incorporated herein by reference.

(d)  Exhibits.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

3