In recent years, a large number of precisely determined crystal structure determinations of zeolites, that is compounds based on open frameworks of coordination tetrahedra, has accumulated. This gives us the opportunity to evaluate them in terms of the flexibility of their bond angles T–X–T which serve as hinges between the coordination tetrahedra in zeolites containing various SiO₄, AlO₄, PO₄ and similarly sized ions. Out of about 7,000 known crystal structure descriptions of zeolites we have selected 1187 which are based on single crystal diffraction studies and have estimated standard deviations of their T–O bond length of 0.01 Å or less. The mean Si–O–Si angle in zeolitic frameworks with T-sites fully occupied by one type of T atoms is 152.9° and these angles range from 127.0° to 180°, the mean for Al–O–Si is 141.9°, ranging from 124.8° to 179.3°. Straight angles Si–O–Si do occur in some zeolites.

近年来，积累了大量精确测定沸石晶体结构的测定，即基于配位四面体开放骨架的化合物。_{这让我们有机会根据它们的键角 T–X–T 的灵活性来评估它们，键角 T–X–T 在含有各种 SiO 4}、AlO ₄、PO ₄的沸石中充当配位四面体之间的铰链和类似大小的离子。在大约 7,000 种已知的沸石晶体结构描述中，我们选择了 1187 种，它们基于单晶衍射研究，并估计其 T-O 键长的标准偏差为 0.01 Å 或更小。在 T 位被一种 T 原子完全占据的沸石骨架中，平均 Si-O-Si 角为 152.9°，这些角度范围为 127.0° 至 180°，Al-O-Si 的平均值为 141.9°，范围从 124.8° 到 179.3°。直角 Si-O-Si 确实出现在某些沸石中。