Location and anisotropic refinement of deuterium atoms in disodium dideuteriumsilicate heptahydrate (D2O) by neutron diffraction; hydrogen bonding at 296 K and thermal properties

A multiple-quantum 23Na MAS NMR study of amorphous sodium gallium silicate zeolite precursors

“…Table 1 Average 23 Na isotropic chemical shifts (d iso , relative to 0.15 M NaCl (aq)) and quadrupolar products (P Q ) for the sodium gallium silicates extracted from centres of gravity of two-dimensional 23 chemically to our sodium gallium silicate samples: sodium silicates, sodium aluminium silicates, sodium aluminates and sodium gallates. [30][31][32][33][34][35][36][37][38][39][40][41] A number of workers have studied a range of crystalline and glassy sodium silicates using 23 Na NMR spectroscopy and some have attempted to establish a correlation between the isotropic chemical shift, d iso , and the local atomic arrangement of atoms about sodium (bond distances, coordination number and geometry). For example, Koller et al 42 derived a ''shift parameter'', A, for a number of crystalline sodium-containing materials by considering the bond valence parameter of each bond to sodium and each individual bond length.…”

“…Also shown are crystallographic parameters relating to the average local environment of sodium in each of the compounds. [30][31][32][33][34][35][36][37][38][39][40][41] In each material, the first coordination shell of sodium consists of between four and six oxygen atoms at mean distances between 2.32 and 2.52 A ˚. The type of atom in the second coordination shell of sodium varies for each compound, but it can be seen that this has little effect on the magnitude of d iso .…”

Hydrothermal Strategies Towards Polyoxofluoromolybdates(VI)

“…As a result, the three crystallographically different sodium cations in adu 4 NaMo 7 O 22 F 3 ·4H 2 O cover the entire spectrum of known coordination geometries for Na + within a single compound: octahedral, tetragonal-pyramidal, and square-pyramidal. Whereas the six-fold coordinations, distorted octahedral and the trigonal-prismatic surroundings, are most common in sodium salts, both trigonal-bipyramidal and tetragonal-bipyramidal geometries have been reported for Na 2 H 2 SiO 4 ·4H 2 O . Recently, tetragonal-bipyramidally coordinated Na + has also been found in sodium-coordinated oligonucleotides .…”