## 3 Results
### Ambient and Accelerated Thermal Stability of Ag\({}_{7}\)NO\({}_{11}\):SiO\({}_{2}\)  
Diffraction patterns of silver oxynitrate and Ag\({}_{7}\):NO\({}_{11}\):SiO\({}_{2}\) containing 0.1:1 SiO\({}_{2}\): were evaluated over a period of four months (16 weeks) under both ambient and elevated temperature storage conditions (40 \({}^{\circ}\)C). Within this timeframe, degradation of solid-state silver oxynitrate was evaluated by monitoring the depletion of the standard Ag\({}_{7}\)NO\({}_{11}\) diffraction peaks: 31.3, 36.3, and 39.7 \({}^{\circ}\)2\(\Theta\) and the onset of the first thermal decomposition product argantic oxide, Equation (4), following standard AgO diffraction patterns peaks: 32.2, 32.4, 37.3, and 38.6 \({}^{\circ}\)2\(\Theta\)[21; 23]. For the purposes of this study, the silver oxynitrate peak at 36.3 \({}^{\circ}\)2\(\Theta\) peak was utilized to distinguish the presence/absence of silver oxynitrate as there are no overlapping impurity or degradation product diffraction peaks at this diffraction angle. At the study commencement, minor silver sulfate (Ag\({}_{2}\)SO\({}_{4}\)) impurities were additionally identified using standard diffraction patterns peaks: 28.1, 31.2, 33.9 \({}^{\circ}\)2\(\Theta\). \[\text{Ag}_{7}\text{NO}_{11}\to 6\text{AgO}+\text{Ag}\text{NO}_{3}+\text{O}_{2} \tag{4}\]  
Following one month of silver oxynitrate storage under ambient conditions, Figure 4A, the primary solid-state compound observed was Ag\({}_{7}\)NO\({}_{11}\) with minor peaks attributed to AgO and Ag\({}_{2}\)SO\({}_{4}\). Following four months of storage at room temperature, AgO and Ag\({}_{2}\)SO\({}_{4}\) alone were observed, consistent with the first thermal decomposition step shown in Equation (4). In parallel, the stability of Ag\({}_{7}\)NO\({}_{11}\):SiO\({}_{2}\) containing 0.1:1 SiO\({}_{2}\):Ag was evaluated under ambient conditions as shown in Figure 4B. Silver oxynitrate was identified as the primary solid-state compound following one month of storage under ambient conditions with minor peaks attributed to AgO and Ag\({}_{2}\)SO\({}_{4}\). Similarly, at four months of storage under ambient conditions, the primary solid-state compound observed was Ag\({}_{7}\)NO\({}_{11}\) with only minor peaks attributed to AgO and Ag\({}_{2}\)SO\({}_{4}\). Storage of silver oxynitrate under elevated temperatures, Figure 5A, was observed to result in multi-stage thermal decomposition processes as shown in Equations (5) to (7) [21; 23]. Within one week of storage under 40 \({}^{\circ}\)C, the predominant solid-state compound was identified as silver nitrate, in good agreement with standard AgNO\({}_{3}\) diffraction peaks: 29.7, 32.8, and 35.3 \({}^{\circ}\)2\(\Theta\). Secondary solid-state compounds were identified as Ag\({}_{7}\)NO\({}_{11}\), AgO, and Ag\({}_{2}\)SO\({}_{4}\). Following 16 weeks of storage at elevated temperatures, the diffraction peak at 36.3 \({}^{\circ}\)2\(\Theta\) for Ag\({}_{7}\)NO\({}_{11}\) was not observed nor were any standard diffraction patterns for AgO. The primary solid-state diffraction patterns identified in the XRD pattern at 16 weeks were in agreement with AgNO\({}_{3}\), Ag\({}_{2}\)O, and Ag (metallic silver), indicative of advanced thermal decomposition pathways as per Equations (5) to (7). In contrast, decomposition of Ag\({}_{7}\)NO\({}_{11}\):SiO\({}_{2}\), containing 0.1:1 SiO\({}_{2}\):Ag, under elevated temperatures was less severe. Retaining Ag\({}_{7}\)NO\({}_{11}\) as the predominant solid-state compound with only minor peaks attributed to AgO and Ag\({}_{2}\)SO\({}_{4}\) after one week and conversion to the first thermal decomposition product, AgO, following 16 weeks of storage under 40 \({}^{\circ}\)C.  
Figure 1: Powder X-ray diffraction of Ag\({}_{7}\)NO\({}_{11}\):SiO\({}_{2}\) (0.0:1 to 0.5:1 molar equivalents SiO\({}_{2}\):Ag). Solid-state silver compounds were identified as silver oxynitrate (Ag\({}_{7}\)NO\({}_{11}\), inverted red triangles) and silver sulfate (Ag\({}_{2}\)SO\({}_{4}\), green circles).