Crystal structure and dynamics of Mg(ND3)6Cl2

Abstract

The crystal structure and dynamics of Mg(ND(3))(6)Cl(2) have been investigated by powder neutron diffraction and molecular dynamics. The powder diffraction data can be well described by 4 partly occupied deuterium sites in a square arrangement around the N atoms, which is seemingly inconsistent with the 3-fold symmetry of the ND(3) molecule. Molecular dynamics show highly correlated rotational and translational motion of the ND(3) molecules which explains the apparent 4-fold symmetry of the deuterium arrangement. A more disordered structure model based on the molecular dynamics results gives a better fit to the experimental data and is in agreement with the 3-fold symmetry of ND(3).

Activation on Ammonia Absorbing Reaction for Magnesium Chloride

“…For Mg(ND 3 ) 6 Cl 2 , Sørby et al reported that the ND 3 molecules in ammine complex phase has highly correlated rotational and translational motions. 19 Thus, it is expected that the degree-of-freedom of NH 3 molecule in Mg(NH 3 )Cl 2 is extremely high. Form the ΔS 0 obtained in this work, the entropy of solid at standard conditions of Mg(NH 3 ) 6 Cl 2 and Mg(NH 3 )Cl 2 were estimated to be S 0 = 352 and 185 J/mol K, respectively (Table S1), 20 where the S 0 per NH 3 of Mg(NH 3 ) 6 Cl 2 and Mg(NH 3 )Cl 2 was described as 59 and 185 J/mol K, respectivaly.…”

A theoretical study on novel alkaline earth-based excess electron compounds: unique alkalides with considerable nonlinear optical responses

“…As a promising candidate material for hydrogen storage, the Mg(NH 3 ) 6 Cl 2 compound has been extensively studied by experimental researchers in recent years. [37][38][39][40] On the basis of its crystal structure, 41 three conformations of the isolated Mg(NH 3 ) 6 Cl 2 molecule were obtained. The resulting geometric structures are depicted in Fig.…”

“…35,36 Nevertheless, Mg(NH 3 ) 6 can be obtained under the existence of Cl À counterions in Mg(NH 3 ) 6 Cl 2 . [37][38][39][40][41] Based on the definition of alkalide, it is interesting to replace one or two Cl À in Mg(NH 3 ) 6 Cl 2 with alkali metal atoms to detect whether novel inorganic Mg-based alkalides can be obtained or not. As for Ca(NH 3 ) 6 , the valence electrons of Ca are pushed out by NH 3 complexants, and delocalized outside the whole structure (see Fig.…”

A nonlinear optical switch induced by an external electric field: inorganic alkaline–earth alkalide

“…41 Nevertheless, with the existence of Cl À counterions, Mg(NH 3 ) 6 Cl 2 can be obtained. [42][43][44][45][46] Li's group 35 used M(NH 3 ) 6 (M ¼ Mg, Ca) to theoretically design a series of novel alkalide molecules with double alkali anions M(NH 3 ) 6 Na 2 and they found that those compounds had large static rst hyperpolarizability (electronic contribution b e 0 ) values ranging from 0 to 1.23 Â 10 5 (a.u.). It was noticed that one of the isomers with centrosymmetry (with D 3d point group) of M(NH 3 ) 6 Na 2 was the most stable, but its b e 0 value was zero.…”