Structure, hydrogen bonding and thermal expansion of ammonium carbonate monohydrate

Abstract

Single-crystal neutron diffraction, ab initio calculations and Raman spectroscopy are applied to understand the structure and hydrogen bonding of ammonium carbonate monohydrate, a hitherto poorly characterized substance, particularly in relation to other ammonium-bearing compounds.

Ab initio simulations of α- and β-ammonium carbamate (NH4·NH2CO2), and the thermal expansivity of deuterated α-ammonium carbamate from 4.2 to 180 K by neutron powder diffraction

“…There is a large degree of anisotropy in the structure upon warming; the greatest expansion is along the b axis, with the a and c axes having similar expansivities. The values of the volumetric thermal expansion coefficient are comparable with water ice and ammonium carbonate monohydrate at the same Figure 9 temperature (Fortes, 2018;Fortes et al, 2014). We find no evidence for negative thermal expansion in the structure.…”

“…The ammonium carbonates are highly anisotropic, typically with one unique axis, and two axes that behave similarly, due to planar layers of interconnected ammonium tetrahedra. Indeed, in ammonium carbonate monohydrate, the c axis has been shown from variabletemperature neutron single-crystal data to exhibit negative linear expansion, whilst the a and b axes exhibit large positive expansivities of similar magnitude (Fortes et al, 2014).…”

Structure, thermal expansion and incompressibility of MgSO4·9H2O, its relationship to meridianiite (MgSO4·11H2O) and possible natural occurrences

“…We also tested two different gradient-corrected functionals (GGAs), specifically those referred to as 'PBE' (Perdew et al, 1996(Perdew et al, , 1997 and 'Wu-Cohen' or 'WC' (Wu & Cohen, 2006). In the past, we have successfully used the PW91 or closely related PBE GGAs for these types of materials (Fortes et al, 2014(Fortes et al, , 2015. However, there is reason to believe that the Wu-Cohen GGA functional is more accurate than PBE for specific types of calculations (e.g.…”

Bidentate and Monodentate Binding of Chromium (VI) on the Acid Scavenger Exchange Resin, MP-Carbonate, as a Function of pH

“…6 a and b and summarized in Table 6. The molecular geometry of CO 3(US-EPA n.d. ) has trigonal planar symmetry (point group D 3 h) (Fortes et al 2014) with bond angles of 118-122°. Chromate adopts a tetrahedral molecular orientat i o n w i t h b o n d a n g l e s b e t w e e n 1 0 6 a n d 112° (McGinnety 1972).…”