Unveiling the structure of aqueous magnesium nitrate solutions by combining X-ray diffraction and theoretical calculations

Abstract

The structure of aqueous magnesium nitrate solution is gaining significant interest among researchers, especially whether contact ion pairs exist in concentrated solutions. Here, combining X-ray diffraction experiments, quantum chemical calculations...

A total scattering study of prenucleation structures in saturated aqueous magnesium sulfate – observation of extended clusters

“…A combined total scattering and computational modelling study was recently reported by Wang and coworkers and this did use an atomistic model to look at the structure of magnesium nitrate and we will compare some of our results to theirs. 25 A similar study was also conducted by Jensen and coworkers looking at amorphous magnesium/calcium carbonates. 26 In the wider context of clustering in solution Sva ¨rd and coworkers 27 have reported impressive studies of molecular systems (fenoxycarb) using a whole barrage of techniques from dynamic light scattering and small angle X-ray scattering to molecular dynamics simulations looking at the molecular clustering in isopropanol solutions.…”

“…The missing 5% are fragments based on higher numbers of coordinated sulfates. distance of 2.1 Å), 25 and the second broader feature describing either far-side sulfate oxygens (O1) or a second solvation shell in the case of water (Ow) with distances in the range 4.20-4.35 Å. In both cases the shorter distances have a narrower distribution possibly providing evidence of contact ion pairing (CIP), as described by Zhang and co-workers.…”

“…A combined total scattering and computational modelling study was recently reported by Wang and co-workers and this did use an atomistic model to look at the structure of magnesium nitrate and we will compare some of our results to theirs. 25 A similar study was also conducted by Jensen and co-workers looking at amorphous magnesium/calcium carbonates. 26…”

“…The numbers observed here are in good general agreement with those reported by Wang and co-workers when comparing to their water-salt ratio of (WSR) 30 – our 2M MgSO 4 solution has a WSR of 24. 25…”

“…The numbers observed here are in good general agreement with those reported by Wang and co-workers when comparing to their water-salt ratio of (WSR) 30 -our 2M MgSO 4 solution has a WSR of 24. 25 Using the values taken from Fig. 4a, which gives the probability of finding different numbers of water molecules (Ow) coordinated to magnesium (Mg1), we see the most probable number is 5 herein formalised as Mg1Á Á ÁOw = 5, and this, paired with the most probable number of coordinated sulfate anions given by Mg1Á Á ÁO1 = 1, gives the 6-coordinate environment depicted in Fig.…”