Preparation and Crystal Structures of the Rare Earth Nitrido-Oxosilicates and Nitridosilicates with the General FormulaR6+x/3Si11N20+xO1−xand the Ideal CompositionsR6Si11N20O andR6.33Si11N21, Respectively (R=Y and Gd–Lu)
Preparation and Crystal Structures of the Rare Earth Nitrido-Oxosilicates and Nitridosilicates with the General FormulaR6+x/3Si11N20+xO1−xand the Ideal CompositionsR6Si11N20O andR6.33Si11N21, Respectively (R=Y and Gd–Lu)
复制标题
分别具有通式R6+x/3Si11N20+xO1−x和理想成分R6Si11N20O和R6.33Si11N21（R=Y和Gd-Lu）的稀土氮化硅酸盐和氮化硅酸盐的制备和晶体结构
DOI：
10.1006/jssc.1996.7258
复制
发表时间：
1997
影响因子：
5.4
通讯作者：
W. Jeitschko
中科院分区：
文献类型：
--
作者：
M. Woike;W. Jeitschko
摘要以多相稀土硅氧化物粉末为原料，与氮气反应合成了9种标题化合物。从已在高频炉中熔化的样品中分离铒化合物的单晶。两个略有不同的三角晶体结构（P 31 c，Z =2）建立从单晶X射线衍射仪数据。在1531个结构因子和68个可变参数下，在Er6Si11N20O晶体中发现了两个完全占据的Er位置：a =977.3（1）pm，c =1059.7（1）pm，R =0.021。第三个铒位置被精炼，部分占据另一个晶体，其组成为Er 6.254（3）Si 11 N 20.762（9）O 0.238（9）：a =978.5（1）pm，c =1064.4（1）pm，R =0.023，884个F值和71个变量。这些透明晶体中氧原子的存在和位置是基于结构化学参数。对于不含氧的晶体，第三个铒位置应具有33%的占有率，对应于式Er 6.33 Si 11 N 21。两个完全占据的铒位置由六个配位，部分占据的铒位置由七个氮（氧）原子配位。硅原子具有四面体排列的四个氮（氧）邻居。一些氮原子仅与一个硅原子键合，但大多数氮原子通过公共角连接两个SiN 4四面体。因此，这些化合物可以基本上被认为是骨架氮硅酸盐。与氧原子具有一个或两个硅邻居的正常氧硅酸盐相比，这些氮硅酸盐的结构还包含连接三个甚至四个SiN 4四面体的氮原子。
Abstract The nine title compounds were prepared by reaction of multiple-phase rare earth silicide oxide powders with nitrogen. Single crystals of the erbium compound were isolated from a sample, which had been melted in a high-frequency furnace. Two slightly different trigonal crystal structures ( P 31 c , Z =2) were established from single-crystal X-ray diffractometer data. Two fully occupied erbium sites were found for a crystal with the composition Er 6 Si 11 N 20 O: a =977.3(1) pm, c =1059.7(1) pm, R =0.021 for 1531 structure factors and 68 variable parameters. A third erbium site was refined with partial occupancy for another crystal with the composition Er 6.254(3) Si 11 N 20.762(9) O 0.238(9) : a =978.5(1) pm, c =1064.4(1) pm, R =0.023 for 884 F values and 71 variables. The presence and the location of the oxygen atoms in these transparent crystals are based on structure-chemical arguments. For a crystal without oxygen the third erbium site should have an occupancy of 33%, corresponding to the formula Er 6.33 Si 11 N 21 . The two fully occupied erbium sites are coordinated by six, the partially occupied erbium site is coordinated by seven nitrogen (oxygen) atoms. The silicon atoms have four nitrogen (oxygen) neighbors in tetrahedral arrangement. Some nitrogen atoms are bonded to only one silicon atom, but most are linking two SiN 4 tetrahedra via common corners. The compounds may therefore be considered essentially as framework nitridosilicates. In contrast to normal oxosilicates, where the oxygen atoms have one or two silicon neighbors, the structures of these nitridosilicates also contain nitrogen atoms which link three or even four SiN 4 tetrahedra.