The Crystallography of Solid Nitrogen Oxides: Sodium Hyponitrite, Potassium Nitrite

摘要

The purpose of the research was to study the crystal structure of sodium hyponitrite and potassium nitrite by the X-ray diffraction method. Three forms of sodium hyponitrite, i.e., anhydrous, octa, and pentahydrate, were obtained. Rotation and zero-level Weissenberg photographs were obtained and analyzed. Patterson projection, Patterson function, Harker section, and electron density contour maps were calculated. The crystal structure of potassium nitrite was redetermined. The cell dimensions were refined by improving the experimental techniques and employing the method of the least squares to minimize error. Instead of a monoclinic unit cell as reported, a rhombohedral cell seems most probable for the KNO2 crystal. The molecule is planar. A phase transformation was found at -17.7C. The thermal properties near the transition were measured.