TY - JOUR
T1 - Si-O Bonded Interactions in Silicate Crystals and Molecules: A Comparison
AU - Gibbs, G.V.
AU - Jayatilaka, Dylan
AU - Spackman, Mark
AU - Cox, D.F.
AU - Rosso, K.M.
PY - 2006
Y1 - 2006
N2 - Bond critical point, local kinetic energy density, G(r(c)), and local potential energy density, V( rc), properties of the electron density distributions, rho(r), calculated for silicates such as quartz and gas-phase molecules such as disiloxane are similar, indicating that the forces that govern the Si-O bonded interactions in silica are short-ranged and molecular-like. Using the G(r(c))/rho(r(c)) ratio as a measure of bond character, the ratio increases as the Si-O bond length, the local electronic energy density, H(r(c)) G(r(c)) + V(r(c)), and the coordination number of the Si atom decrease and as the accumulation of the electron density at the bond critical point, rho(r(c)), and the Laplacian, del(2)rho(r(c)), increase. The G(r(c))/rho(r(c)) and H(r(c))/rho(r(c)) ratios categorize the bonded interaction as observed for other second row atom M-O bonds into discrete categories with the covalent character of each of the M-O bonds increasing with the H(r(c))/rho(r(c)) ratio. The character of the bond is examined in terms of the large net atomic charges conferred on the Si atoms comprising disiloxane, stishovite, quartz, and forsterite and the domains of localized electron density along the Si-O bond vectors and on the reflex side of the Si-O-Si angle together with the close similarity of the Si-O bonded interactions observed for a variety of hydroxyacid silicate molecules and a large number of silicate crystals. The bond critical point and local energy density properties of the electron density distribution indicate that the bond is an intermediate interaction between Al-O and P-O bonded interactions rather than being a closed-shell or a shared interaction.
AB - Bond critical point, local kinetic energy density, G(r(c)), and local potential energy density, V( rc), properties of the electron density distributions, rho(r), calculated for silicates such as quartz and gas-phase molecules such as disiloxane are similar, indicating that the forces that govern the Si-O bonded interactions in silica are short-ranged and molecular-like. Using the G(r(c))/rho(r(c)) ratio as a measure of bond character, the ratio increases as the Si-O bond length, the local electronic energy density, H(r(c)) G(r(c)) + V(r(c)), and the coordination number of the Si atom decrease and as the accumulation of the electron density at the bond critical point, rho(r(c)), and the Laplacian, del(2)rho(r(c)), increase. The G(r(c))/rho(r(c)) and H(r(c))/rho(r(c)) ratios categorize the bonded interaction as observed for other second row atom M-O bonds into discrete categories with the covalent character of each of the M-O bonds increasing with the H(r(c))/rho(r(c)) ratio. The character of the bond is examined in terms of the large net atomic charges conferred on the Si atoms comprising disiloxane, stishovite, quartz, and forsterite and the domains of localized electron density along the Si-O bond vectors and on the reflex side of the Si-O-Si angle together with the close similarity of the Si-O bonded interactions observed for a variety of hydroxyacid silicate molecules and a large number of silicate crystals. The bond critical point and local energy density properties of the electron density distribution indicate that the bond is an intermediate interaction between Al-O and P-O bonded interactions rather than being a closed-shell or a shared interaction.
U2 - 10.1021/jp063881q
DO - 10.1021/jp063881q
M3 - Article
C2 - 17107120
VL - 110
SP - 12678
EP - 12683
JO - The Journal of Physical Chemistry Part A: Molecules, Spectroscopy, Kinetics, Environment and General Theory
JF - The Journal of Physical Chemistry Part A: Molecules, Spectroscopy, Kinetics, Environment and General Theory
SN - 1089-5639
IS - 46
ER -