Crystal structure of aluminium iodate–hydrogen iodate–water (1/1/6) and preparation of anhydrous aluminium iodate

Abstract

The crystal structure of the title compound has been determined by Patterson and Fourier methods using threedimensional X-ray data and has been refined by a full-matrix least-squares procedure to R = 0.029 for 2 546 observed reflections. The crystals are hexagonal, space group P63 with a = 16.1 07(2), c = 12.378(2) A, Z = 6. The transformation of the structure to that of anhydrous aluminum iodate (hexagonal, a = 8.97, c = 5.25 A) is considered. The structure can be formulated as [Al(OH,)63+] [103-]2[H1,06-]*H10, and contains a very short non-bonded oxygen-iodine contact of 2.476 A. Institute for Soil Research, Craigiebuckler, Aberdeen AB9 2QJ PREPARATION of the mixed anion salt A1[I03],[N0,]-6H,O using an A1 : [IOJ-ratio >1 : 3 (or better, 1 : 6) results in the crystallisation of the acid salt Al[IOJ,-2HI03*6H20 after all the nitrate salt has been removed from the solution. The crystal structure of aluminium iodate nitrate has already been reported and the structure of the acid iodate is of interest because of the different behaviour of the two compounds on heating. AlJII0,],[N03]*6H,0 loses six water molecules and 20% of the nitrate (by analysis) at 200 "C. The remainder of the nitrate is removed between 300 and 340 "C and the [103]-decomposes at 425 "C. Up to the decomposition temperature, the powder diffraction pattern is not noticeably altered; a result of the fact that the positions of the iodate ions, which contain 60% of the scattering material, are unaltered. A1[I0,],~2HI0,*6H20, on the t Present address .-N.Z. Fertiliser Manufacturers Research Association,

Improving the Explosive Performance of Aluminum Nanoparticles with Aluminum Iodate Hexahydrate (AIH)

“…In Cradwick et al . 11 , the evaporation of the hydrate layer in AIH is reported to occur at 135 °C. To test the hypothesis that Al oxidation in AIH mixtures occur when the hydrate layer is removed, a DSC experiment was performed to examine heat flow under equilibrium conditions.…”

“…When exposed to highly acidic solutions (i.e., pH < 4), Al 2 O 3 becomes soluble and dissolves in solution 11 . The solubility of Al 2 O 3 in acidic solutions has been utilized in the synthesis of Al energetic materials to remove the Al 2 O 3 passivation layer surrounding Al particles and replace Al 2 O 3 with a reactive salt 12,13 .…”

A case of polytypism in hydrated oxysalts: the crystal structure of Mg3(P04)2 22 H20-II

“…In both AI and All structures the polyhedra are usually arranged on layers, which often show a pseudo-hexagonal symmetry as in the salt studied here: cf. Zn(C104)2 • 6H20 (Ghosh and Ray, 1977) and Na2HP04 12H20 (Catti, Ferraris, and Ivaldi, 1978); in several cases the layer symmetry is exactly hexagonal, as in MgS03-6H20 (Flack, 1973), Sm(Br03)3 • 9 H20 (Sikka, 1969), NaAl(S04)212H20 (Cromer, Kay, and Larson, 1967), A1(I03)2N03-6H20 (Cradwick and de Endredy, 1975) and A1H2(I03)5-6H20 (Cradwick and de Endredy, 1977). Probably, the hydrogen bonding configuration is optimized by this type of polyhedra packing.…”

Discovery of &lt;i&gt;β&lt;/i&gt;-HIO&lt;sub&gt;3&lt;/sub&gt;: A Metastable Polymorph of HIO&lt;sub&gt;3&lt;/sub&gt;

“…I 2 O 5 , HIO 3 , HI 3 O 8 , I 4 O 9 ) are compounds with unique optical properties and potential for high energy release. The unique optical properties of iodine oxides, specifically iodic acid (HIO 3 ), are a result of the non-centrosymmetric space group P2 1 2 1 2 1 [1], and have led to the synthesis of different aluminum iodate species [2] [3]. Iodine oxides are also appealing for use as an oxidizer when combined with aluminum fuel particles.…”

“…The aluminum and iodine oxide reactions also have the potential to disperse high temperatures and aerosolized iodine species that can kill bacterial agents [5]. The optical properties and potential for energy release of iodine oxides are controlled by the crystalline structure of precipitated HIO 3 product [2] [3] [4].…”