Figure 2
Plot of the a parameter against x for a range of Mg-Al (circles) and Mg-Ga (triangles) layered double hydroxides (LDH) reported in the literature; the data for the Mg-Al LDH involve a variety of interlayer anions (i.e. OH-, CO32-, NO3-, Cl-) and are from: Mg-Al: Bellotto et al., 1996BB2; Bîrjega et al., 2005BB4; Brindley & Kikkawa, 1979BB5; Budhysutanto et al., 2011BB7; Gastuche et al., 1967BB13; Han et al., 1998BB14; Jinesh et al., 2010BB15; Kaneyoshi & Jones, 1999BB16; Kukkadapu et al., 1997BB17; Mascolo & Marino, 1980BB19; Miyata, 1980BB21; Pausch et al., 1986BB22; Rao et al., 1998BB23; Sato et al., 1988BB27; Shen et al., 1994BB28; Valente et al., 2011BB29; Xu & Zeng, 2001BB33; Yun & Pinnavaia, 1995BB34; Mg-Ga: Bellotto et al., 1996BB2; López-Salinas et al., 1997BB18. The full lines are the result of the linear regression analyses of both sets of data and the filled diamond represents the [beta] polymorph of magnesium hydroxide (i.e. brucite). The dashed lines represent the values of a calculated from theory [using equation (15) in Richardson, 2013bBB25]. The open diamond can be taken to represent a theoretical [alpha] form of magnesium hydroxide (Richardson, 2013bBB25). The bold numbers correspond to the ordered distributions of M3+ ions in the octahedral layer that are illustrated in Fig. 1[link]; the three compositions that are labelled `x' are explained in the text.  [article HTML]