- Complex Salts Containing [Pd(NH3)4]2+ Cations and WO42? and W7O246? Anions: The Precursors of Pd–W Metal Alloys
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Two crystal structures containing [Pd(NH3)4]2+ cations and WO42? and W7O246? anions are studied. For the [Pd(NH3)4]WO4 structure at 150 K the following crystallographic data are obtained: a = 7.4626(3) ?, c = 15.5718(8) ?, space group I41/amd, V = 867.20 ?3, Z = 4. With increasing temperature to 400 K, the unit cell parameters change in different directions: a increases by 0.032 ?, c decreases by 0.036 ?. The total increase in the unit cell volume is 5 ?3. In a range of 150 K to 400 K, the observed W-O distances decrease by 0.019 ? from 1.778(18) ? to 1.759(3) ?. For the [Pd(NH3)4]3W7O24·4.4H2O structure at 298 K the crystallographic data are as follows: a = 8.3409(2) ?, b = 22.2654(6) ?, c = 10.5450(3) ?, β = 104.449(1)°, space group P21/m, V = 1896.41 ?3, Z = 2. In the heptatungstate anion the shortest are the W—O distances with the terminal O atoms (1.731–1.745 ?). The distances to the bridging O atoms connecting two W atoms are 1.930–2.406 ?; those connecting three W atoms are 1.882–2.234 ?, and those connecting four W atoms are 2.192–2.220 ?. It is shown that the [Pd(NH3)4]3W7O24·4.4H2O structure has a pseudohexagonal motif in the a direction. The thermal decomposition of the salts is performed in the presence of LiH in the He atmosphere at 1273 K. The ex situ powder X-ray diffraction study reveals the formation of Pd–W alloys.
- Gromilov, S. A.,Khranenko, S. P.,Komarov, V. Yu.,Sukhikh, A. S.
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p. 449 - 455
(2020/07/31)
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