Materials Data on Ca2UO17 by Materials Project
(Ca2UO16)2O2 crystallizes in the orthorhombic Pbcn space group. The structure is three-dimensional and consists of four water molecules and one Ca2UO16 framework. In the Ca2UO16 framework, Ca is bonded in a 9-coordinate geometry to nine O atoms. There are a spread of Ca–O bond distances ranging from 2.37–2.86 Å. U is bonded in a distorted linear geometry to eight O atoms. There are a spread of U–O bond distances ranging from 1.86–2.41 Å. There are eight inequivalent O sites. In the first O site, O is bonded in a water-like geometry to one Ca and one U atom. In the second O site, O is bonded in a bent 150 degrees geometry to one Ca and one O atom. The O–O bond length is 1.25 Å. In the third O site, O is bonded to two equivalent Ca, one U, and one O atom to form a mixture of distorted edge, corner, and face-sharing OCa2UO trigonal pyramids. The O–O bond length is 1.49 Å. In the fourth O site, O is bonded in a bent 120 degrees geometry to one Ca and one O atom. The O–O bond length is 1.26 Å. In the fifth O site, O is bonded in a bent 150 degrees geometry to one Ca and one O atom. In the sixth O site, O is bonded to two equivalent Ca, one U, and one O atom to form a mixture of distorted edge, corner, and face-sharing OCa2UO trigonal pyramids. In the seventh O site, O is bonded in a bent 120 degrees geometry to one Ca and one O atom. In the eighth O site, O is bonded in a 2-coordinate geometry to one U and one O atom. The O–O bond length is 1.32 Å.