Structure of strontium hydroxide octahydrate, Sr(OH)₂·8H₂O, at 20, 100 and 200 K from neutron diffraction

Abstract

The crystal structure of Sr(OH)2*8H2O has been determined at 20, 100 and 200 K from neutron diffraction data. The structure consists of double layers of H2O and OH- ions separated by Sr2+ along the c axis. The Sr2+ ions are eight-coordinated by water O atoms in a square antiprism configuration. Each H2O molecule is engaged in three hydrogen bonds. The OH- ions form chains of acceptor and donor bonds along the fourfold axis with O atoms engaged in four bonds with H2O molecules, such that both non-equivalent O atoms have square-pyramidal environments of five H atoms and the overall bonding configurations of distorted octahedra.

Stable strontium isotope fractionation in synthetic barite

“…The initial guess for the configuration of each substituted 8 structure was based on modeling with empirical potentials (Wahid et al, 2002) using the GULP software package (Gale and Rohl, 2003), followed by relaxation using density functional theory. (Mathew, 1998;Ricci et al, 2005) (Takagi et al, 1982;Agron and Busing, 1986;Abrahams and Vordemvenne, 1995). 88 Sr/ 86 Sr fractionations in SrO and SrF 2 can 9 also be calculated using well-calibrated empirical force field models, providing an important check on model accuracies.…”

The importance of second shell effects in the simulation of hydrated Sr2+hydroxide complexes

“…26,29 Therefore, a system which contains a direct Sr 2+ -OHinteraction with the coordinated OHion involved in two strong hydrogen bonds as a donor and one weak hydrogen bond as an acceptor (e.g. 26,29 Therefore, a system which contains a direct Sr 2+ -OHinteraction with the coordinated OHion involved in two strong hydrogen bonds as a donor and one weak hydrogen bond as an acceptor (e.g.…”

“…D'Angelo and coworkers 18 analysed the data based on molecular dynamics simulations and included multielectron excitations in their model to obtain 10.3 as an average coordination number. 27 Sr(OH) 2 8H 2 O has an entirely different structure: based on XRD19,28 and neutron diffraction studies,29 oxygen atoms from eight water molecules coordinate the Sr 2+ ion in a tetragonal antiprismatic conformation, with each water engaged in at least in three hydrogen bonds. Sr 2+ hydroxide can be crystallised in several hydrate forms: Sr(OH) 2 , Sr(OH) 2 H 2 O and Sr(OH) 2 8H 2 O.…”

Systematic prediction of new ferroelectrics in space group R3. II

“…(2) Coordination differences about the two independent Li atoms, also the tetrahedral coordination of three Li and H3 about O5 with d O5-H3 = 0.60 Å , where $ 1.00 Å is normal, e.g. Ricci et al (2005), reduce the confidence level required for property prediction. (3) Occupation of both Cs and O7 sets of x,y,z and y,x,z sites would satisfy the criteria for ferroelectricity.…”