Schwendtner Karolina, Kolitsch Uwe
Universität Wien, Institut für Mineralogie und Kristallographie, Geozentrum, Althanstrasse 14, A-1090 Wien, Austria.
Acta Crystallogr C. 2004 Sep;60(Pt 9):i79-83. doi: 10.1107/S0108270104015938. Epub 2004 Aug 11.
The crystal structures of hydrothermally synthesized potassium scandium hydrogen arsenate(V), KSc(HAsO4)2, (I), and rubidium scandium diarsenate(V), RbScAs2O7, (II), were determined from single-crystal X-ray diffraction data collected at room temperature. Compound (I) represents a new microporous structure type, designated MCV-3, which is characterized by a three-dimensional framework of corner-sharing alternating ScO6 octahedra and HAsO4 tetrahedra. Intersecting tunnels parallel to [101] and [110] host eight-coordinate K atoms. There is one hydrogen bond of medium strength [O...O = 2.7153 (18) A]. Compound (II) is the first reported diarsenate with a KAlP2O7-type structure and is isotypic with at least 27 A(I)M(III) diphosphates. The average Sc-O bond lengths in (I) and (II) are 2.09 (2) and 2.09 (3) A, respectively. The K and Sc atoms in (I) lie on an inversion centre and a twofold axis, respectively. All atoms in (II) are in general positions.
通过在室温下收集的单晶X射线衍射数据，确定了水热合成的砷酸氢钪钾（V）KSc(HAsO4)2（I）和二砷酸钪铷（V）RbScAs2O7（II）的晶体结构。化合物（I）代表一种新的微孔结构类型，命名为MCV-3，其特征是由共享角顶的交替ScO6八面体和HAsO4四面体构成的三维骨架。平行于[101]和[110]的交叉隧道容纳八配位的K原子。存在一个中等强度的氢键[O...O = 2.7153 (18) Å]。化合物（II）是首个报道的具有KAlP2O7型结构的二砷酸盐，并且与至少27种A(I)M(III)二磷酸盐同型。（I）和（II）中Sc-O键的平均键长分别为2.09 (2) Å和2.09 (3) Å。（I）中的K和Sc原子分别位于对称中心和二重轴上。（II）中的所有原子都处于一般位置。
