Barrerite single crystals from Kuiu Island (Alaska) were treated in a ND4Cl aqueous solution to obtain the ND4-exchanged form. The crystal structure of the exchanged barrerite (Na0.85K0.24Mg0.38Ca1.30Ba0.02(ND4)10.52 Al15.01Si56.99O144 ·41D2O, a = 13.601 Å, b = 18.232 Å, c = 17.810 Å, space group Fmmm) was studied by single crystal neutron diffraction on data collected at 20 K at the D19 line at ILL (Grenoble). A comparison with a previously studied NH4-exchanged barrerite showed that the framework was identical in the two refinements, and that a substantial agreement occurred also in the extraframework content in the residual cations, in D2O molecules and in ND4+ ions. Surprisingly, no evidence was found of D atoms either around nitrogen or around the oxygens of water molecules. This result could be interpreted as a consequence of the partial occupancy of the extraframework sites and the large distances of these sites from framework oxygens, with consequent weak hydrogen bonds, which make a disorder in the orientation of D2O and ND4 groups highly probable.

You do not have access to this content, please speak to your institutional administrator if you feel you should have access.