Interlayer interactions in M(OH)₂: a neutron diffraction study of Mg(OH)₂

Abstract

Magnesium hydroxide, Mg(OH)2: M r = 58.3, trigonal, P3ml, a=3.148(1), c=4.779(2),~, V--41.015,~ 3, D x = 2.36gcm -3 at room temperature; a = 3.145 (1), c = 4.740 (2) A, V = 40.602,~3, Dx = 2.39 gcm -3 at 70 K; Z --1, 2 = 0.8330 (5) A, /z = 1.78 cm -1, F(000) = 9.503 fm; final R = 2.42, wR = 2.40, S --3.22 for 82 unique reflections at room temperature; R = 1.84, wR = 1.82, S = 2.54 for 81 unique reflections at 70K. Refinements have been carried out using anisotropic thermal coefficients for all atoms. To interpret the very large thermal motion of the H atom, subsequent refinements have been carried out with an anharmonic model and with a three-site split-atom model, and results are compared with those previously reported for Ca(OH) 2. By comparing the interatomic distances O...O, H...H and H...O in the interlayer spacing of Mg(OH)2 and Ca(OH) 2, as well as their temperature dependence, the nature and the strength of interlayer interactions in both compounds are discussed.

Identification of intrinsic hydrogen impurities in ZnO with 1H solid-state nuclear magnetic resonance spectroscopy

“…There is a relationship 'ı iso (ppm) = 79.05 − 0.255d(O H· · ·O) (pm)' between the hydrogen bond length (d(O H· · ·O)) and the 1 H chemical shift (ı iso ). [34,42] According to the d(O H· · ·O) distance (∼280 ppm) [43] in Zn(OH) 2 , the calculated chemical shift in Zn(OH) 2 is about ∼7 ppm, while 1 H chemical shift for Mg(OH) 2 is less than 1 ppm based on the calculation [44]. Therefore, according to the crystal structure and previous report, the peak with relatively high shift (∼4.9 ppm) should arise from hydroxyl groups.…”

Mg(OH)2−WS2 van der Waals heterobilayer: Electric field tunable band-gap crossover

“…The optical spectra of different stacking types exhibit distinct properties. Like Ca(OH) 2 , Mg(OH) 2 has a layered structure in its bulk form, possessing the trigonal symmetry of the space group P 3m1 (brucite) [34][35][36]. Mg(OH) 2 itself is a wide-gap insulator with a band gap of 7.6 eV found experimentally for the bulk structure [37].…”

Oxygen K-edge electron energy loss spectra of hydrous and anhydrous compounds

“…In addition, the theoretical model has a perfect alignment of the OH groups parallel to the c-axis. This is just a first approximation to the disordered arrangement of the OH groups in the real structure, as neutron diffraction data is best described by models in which the hydrogen atoms are distributed over three sites (Desgranges et al 1996, Chakoumakos et al 1997. However, Figure 3.…”