Abstract

An accurate X-ray diffraction study of cordierite mineral, the simplified chemical formula of which is Mg₂Al₄Si₅O₁₈, is performed. The main octahedral position contains magnesium, iron, and aluminum ions, as well as traces of manganese. Alkaline cations are localized within large channels formed by six AlO₄ and SiO₄ tetrahedra at the level z = 0. Water and carbon-dioxide molecules are located within the same vertical channels as sodium ions but at the level z = 1/4; they alternate from one cell to another. The CO₂ molecule is elongated along the a axis of the cell and rotates around the central carbon atom (0, 0, 0.25) by an angle of ~10°. Several orientations of the water molecule are observed. The mutual ordering of the molecules is hindered in the range 91–295 K due to intense interorientational transitions and the duration of residence of the water molecules in incoherent intermediate states.

中文翻译：

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天然堇青石结构通道中的少量水和二氧化碳杂质的定位

摘要

进行了堇青石矿物的精确X射线衍射研究，堇青石矿物的简化化学式为Mg ₂ Al ₄ Si ₅ O ₁₈。主要的八面体位置包含镁，铁和铝离子，以及痕量的锰。碱性阳离子位于z = 0的六个AlO ₄和SiO ₄四面体形成的大通道内。水和二氧化碳分子与钠离子位于相同的垂直通道内，但z = 1/4；它们从一个单元切换到另一个单元。CO ₂分子沿a方向伸长并围绕中心碳原子（0、0、0.25）旋转〜10°角。观察到水分子的几种取向。由于强烈的原点跃迁和水分子在非相干中间态中的停留时间，在91–295 K范围内阻碍了分子的相互排序。