Indicated hydrogen method hydrides

As mentioned in Sect. 3.2.3 a drawback of this method is the formation of a byproduct, which is salt, which reduces the overall hydrogen content of the synthesized mixture. Another peculiarity of this synthesis method is a complete lack of XRD peaks corresponding to a crystalline synthesized borohydride in the mixture in the right-hand side of the reaction of (3.37). Only the peaks of either LiCl or NaCl are present. On the other hand, the Raman spectra seem to indicate the presence of borohydride. Nakamori et al. [173, 174] interpreted this peculiar behavior as arising most likely due to disordering of the crystal structure of a synthesized borohydride, whatever it means for a sohd state hydride. Application of MCAS to the synthesis of Mg(BH )2 will be discnssed later in the text. 

Solid-state nuclear magnetic resonance (NMR) has been extensively used to assess structural properties, electronic parameters and diffusion behavior of the hydride phases of numerous metals and alloys using mostly transient NMR techniques or low-resolution spectroscopy [3]. The NMR relaxation times are extremely useful to assess various diffusion processes over very wide ranges of hydrogen mobility in crystalline and amorphous phases [3]. In addition, several borohydrides [4-6] and alanates [7-11] have also been characterized by these conventional solid-state NMR methods over the years where most attention was on rotation dynamics of the BHT, A1H4, and AlHe anions detection of order-disorder phase transitions or thermal decomposition. There has been little indication of fast long-range diffusion behavior in any complex hydride studied by NMR to date [4-11]. 

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