Physiochemical Characterization of Iodine (V) Oxide Part II: Morphology and Crystal Structure of Particulate Films

Abstract

Abstract:In this study, the production of particulate films of iodine (V) oxides is investigated. The influence that sonication and solvation of suspended particles in various alcohol/ketone/ester solvents have on the physical structure of spin or drop cast films is examined in detail with electron microscopy, powder x-ray diffraction, and UV-visible absorption spectroscopy. Results indicate that sonicating iodine oxides in alcohol mixtures containing trace amounts of water decreases deposited particle sizes and produces a more uniform film morphology. UV-visible spectra of the pre-cast suspensions reveal that for some solvents, the iodine oxide oxidizes the solvent, producing I2 and lowering the pH of the suspension. Characterizing the crystals within the cast films reveal their composition to be primarily HI3O8, their orientations to exhibit a preferential orientation, and their growth to be primarily along the ac-plane of the crystal, enhanced at higher spin rates. Spin-coating at lower spin rates produces laminate-like particulate films versus higher density, one-piece films of stacked particles produced by drop casting. The particle morphology in these films consists of a combination of rods, plates, cubes, and rhombohedra structure.

Iodine Pentoxide Nano‐rods for High Density Energetic Materials

“…3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 powder due to absorbed water, which is coupling with I 2 O 5 resulting of HI 3 O 8 . This behavior was described in detail in reference [16]. The comparison between the data provided in Figure 3a-d shows that one step dehydration appears in the range of 145-210 8C.…”

“…The processing of iodine pentoxide in alcohols is important step in many applications such as thin film casting or self-assembly. It was shown previously that sonication of iodine pentoxide in alcohols can convert it into HI 3 O 8 [16]. In the case of sonication of iodine pentoxide nano-rods in 2-propanol for 30 min, the DTA/TG analysis shows nearly 100 % transformation of iodine pentoxide into HI 3 O 8 .…”

“…Primarily, the commercial I 2 O 5 particles contain significant amount of HI 3 O 8 contamination due to a strong hygroscopic nature of I 2 O 5 [15]. Moreover, it was shown for submicron size particles the complete transition of I 2 O 5 to HI 3 O 8 in open air (40 % relative humidity) occurs in 120 min [16]. The particles compositions are very sensitive from environmental variation and, thus, sample storagehandling-preparation was performed under 99.98 % nitrogen environment in glove-box.…”

Reaction Kinetics and Combustion Dynamics of I₄O₉and Aluminum Mixtures

“…Water is still the catalyst in crystal structure formation. The synthesis method of I 2 O 5 and I 4 O 9 which form an amorphous structure instead of a crystalline structure is the reason water absorption is seen at lower RH (i.e., 20%) than what was required to start absorption in previous studies (i.e., 70-80% RH) 5,17 . In summary, the iodine compounds' amorphous structure may promote absorption of hydrated species and formation of iodic acids.…”

“…There are many iodine oxide compounds (e.g., HIO 3 , HI 3 O 8 , I 2 O 5 , I 4 O 9 ) but the one most commonly studied for reaction with aluminum (Al) is diiodide pentoxide, I 2 O 5 [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] . There are reasons for favoring I 2 O 5 for combustion with Al: (1) I 2 O 5 has an oxidation state of five which makes it a strong oxidizer for combustion applications; (2) I 2 O 5 is semi-stable, depending on atmospheric conditions, and easily handled in powder form; and (3) I 2 O 5 is relatively easy to produce and readily available.…”