Azides strontium

Strontium azide, Sr(N3)2, a white, hygroscopic salt, dissolves in water (31.4% at 16°C) and is practically insoluble in ethanol (solubility at 16 C, 0.09% [62]) and acetone. The compound decomposes at 140°C [62] and deflagrates when heated above 194°C [85,115]. Sr(N3)2 is made by the methods described for the calcium salt [62,74,75,116,117,119-122,123]. The Wislicenus process is less advisable here, as Sr(N3)2 is formed at 140-155°C, which is already within the range of its thermal decomposition. 

---

Strontium azide, 4785 Styrene, 2945 Tetracyanoethylene, 2629 Tetraethyllead, 3095 Tetramethyl-2-tetrazene, 1759 Tetrasulfur tetranitride, 4770... 

Sodium azide, 4758 Sodium triazidoaurate( ), 0113 Strontium azide, 4785... 

The more recent investigations by Llewellyn and Whitmore [9] with strontium azide, for example, have confirmed the above findings. The distances between the atoms of nitrogen are 1.12 A, and between the furthest atoms of nitrogen in the two N3 groups and the atom of strontium 2.63 and 2.77 A respectively. 

Strontium azide possesses similar properties, but is highly sensitive to the action of even weak acids (e.g. with C02 it forms SrC03) and easily is hydrolysed. 

Barium and strontium azides are used in the manufacture of valves in radio technology. 

J. Maggs, The Action of Ultraviolet Radiation on Barium and Strontium Azides , PrRoySoc A172, 299-314(1939) 17)N.F. Mott, On... 

Moore, Thermal Decomposition of Strontium Azide , Nature 205, 1209-11 (1965)... 

SrN6 (c). Wohler and Martin1 measured the heat of decomposition of strontium azide to be 49.0. 

Strontium azide, 4779 Styrene, 2940 Tetracyanoethylene, 2625 Tetraethyllead, 3089 Tetramethyl-2-tetrazene, 1753 Tetrasulfur tetranitride, 4764... 

Among the Group IIA salts, indications are that strontium azide 24) has an ionic lattice with the cations surrounded by eight near-neighbor azide ions. Barium azide, however, has a structure of lower symmetry (25) which shows some departures from a purely ionic lattice. This is evident from its non-totally reflecting reststrahlen infrared spectrum 26) and the presence of asymmetrical Ni ions (c/Table 2). 

Thermal decompositions of barium and strontium azides, preirradiated with 1 MeV gamma rays, were conducted by Prout and Moore [78,79]. With dehydrated barium azide a total gamma dose of 20 Mrad (2.24 X 10 R) eliminated the induction period and increased the acceleration of the decomposition. A somewhat greater effect was evidenced with strontium azide. Avrami et al. [80] subjected barium azide to Co gamma radiation to exposure levels up to 1 XIO R (Table XIII). Differential thermal analyses (Figure 16) showed a steady decomposition of the sample, and after 1 X 10 R exposure (W hr at room temperature), infrared analysis indicated that the residue was in the form of barium carbonate. 

Most of the studies conducted on azides irradiated with X-rays have involved the changes caused in the subsequent thermal decomposition of the samples. Erofeev and Sviridov [90] studied the effects of moisture and aging on barium azide. An increased decomposition rate was noted with strontium azide preirradiated with X-rays and decomposed at 126°C [91]. Zakharov and coworkers... 

UV irradiation of other azides was conducted by Muller and Brous on sodium azide [99], by Garner and Maggs on barium and strontium azides [113], by Mott on metal azides [114], and by Boldyrev and Skorik on silver and barium azides [115]. Sodium, strontium, and barium azides are decomposed by UV light at room temperature, and their thermal decomposition is accelerated by preirradiation. Boldyrev et al. found that irradiating silver azide with UV light or X-rays at the instant of decomposition had no effect on the rate of its thermal decomposition. 

Strontium azide can be prepared from the carbonate in aqueous hydrazoic acid its structure contains square antiprisms centered by Sr atoms [37, 152]. The structure is shown in Fig. 18 and is reminiscent of the structure of the alkali... 

Strontium azide crystallizes in an orthorhombic Fddd space group with eight molecules per unit cell. The crystal structure of Sr(N3)2 was determined from single-crystal data by Llewellyn and Whitmore [36] and was refined later with anisotropic temperature factors by Pringle and Noakes [10]. The molecular packing is a layer structure type the N3 groups are lying in narrow layers oriented perpendicular to the a axis and centered at jc = 0, 1/4, etc., with their axes parallel to the layer and the Sr atoms are on the planes at jc = 1/8, 3/8, etc. The... 

Strontium azide is considered with Ba(N3)2 because both contain divalent metal ions of group IIA of the periodic table, have two formula units in the primitive unit cell of the crystal, and exhibit explosive behavior under appropriate conditions. The structure of Sr(N3)2 is orthorhombic [81] and, thus far, only IR reflection [80] and transmission [79] data from polycrystalline samples have been obtained (Table XI). Again, the results are in agreement given that the reflection data show only two broad bands. 

Early studies made in conjunction with thermal decomposition experiments [185] showed that for barium and strontium azide, preirradiation with UV light shortened the time elapsed before a previously selected pressure was achieved during thermal decomposition. It was observed that the UV light increased the number of centers at which small aggregates of barium metal or barium nitride could form during the subsequent thermal decomposition. Prolonged illumination was also observed to produce nuclei directly. In contrast, preirradiation of potassium azide with UV light had no effect on its subsequent thermal decomposition [210]. 

Strontium azide Sr(N3)2 More endothermic than calcium azide ... 

---