| 摘要 |
<p>The invention relates to oxides corresponding to centrosymmetrical phases of formula (I): A2+2x(NbO)2-y (MO)ySi4-zXzO12, where: x « 2, the value x = 2 being a structural limit, y varies from 0 to 2 and z from 0 to 4, A stands for potassium or several atoms of alkaline metals present simultaneously, M stands for a metal or several metals present simultaneously which adopt(s) an octahedral co-ordinance close to that of niobium, in particular Ta and/or Ti, and X stands for an element or several elements present simultaneously which adopt(s) a tetrahedral co-ordinance close to that of silicon, in particular Ge and/or P and/or As. These oxides can be used, in particular, in non-linear optics.</p> |
