We report a novel synthesis of stable doped solid carbon monoxide (p-CO) via hard X-ray irradiation of strontium oxalate at ambient conditions and high pressure. We also show via mid-and far-infrared (IR) techniques that CO2 produced via X-ray photochemistry remained trapped within the recovered sample for many months in contrast to pure p-CO which decomposes in days. Our results demonstrate that p-CO doped with carbonates (as verified with IR and Extended X-ray Absorption Fine Structure spectroscopies) is relatively stable, enabling longer term and practical use of this novel material for CO2 storage or as a novel electrical/optical material. (C) 2017 Elsevier B.V. All rights reserved.