Ternary Rare Earth Transition Metal Zinc Compounds RT2Zn20 with T = Fe, Ru, Co, Rh, and Ni
Ternary Rare Earth Transition Metal Zinc Compounds RT2Zn20 with T = Fe, Ru, Co, Rh, and Ni
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三元稀土过渡金属锌化合物 RT2Zn20，其中 T = Fe、Ru、Co、Rh 和 Ni
DOI：
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发表时间：
1997
期刊：
影响因子：
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通讯作者：
U. Rodewald
中科院分区：
文献类型：
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作者：
Tono Nasch;W. Jeitschko;U. Rodewald
在氩气气氛下，对单质组分进行冷压球团退火，制备了48个新化合物RT2Zn20。由TbFeiZn20 （a= 1411.1(1) pm）、YRu2Zn20 （a= 1422.6(1) pm）、DyRu2Zn20 （a= 1422.1(1) pm）、GdCo2Zn20 （a= 1406.0(1) pm）、DyRh2Zn20 （a= 1418.2(1) pm）、TmNi2Zn20 （a= 1401.6(1) pm）的单晶衍射数据细化到R = 0.011 ~ R - 0.024之间的常规残差，得到立方CeCr2Al20型结构（Fd3 _ _ _ _ m, Z = 8）。com - pounds有两种倾向，因此m - like六边形对称，以立方[111]轴作为轴w，具有伪六边形对称。这些细胞体积的微小不一致表明与理想的细胞位置有轻微的偏差。然而，除了TmNi2Zn20的1个锌位外，该结构的5个原子位均在误差范围内被完全占据。稀土原子s的配位是一个配位数为（CN） 16的Frank-K异形多面体。过渡金属原子以二十面体锌配位（cn12）占据位置w。三个锌位中有两个为锌原子的五角形配位，由稀土和/或过渡金属原子（cn12）覆盖，而第三个锌位有12个锌邻居，形成六角形配位，由2个稀土原子（cn14）覆盖。
Forty eight new compounds RT2Zn20 were prepared by annealing cold-pressed pellets of the elemental components in an argon atmosphere. They crystallize with the cubic CeCr2Al20 type structure (Fd3̅̅m , Z = 8), which was refined from single-crystal diffractometer data of TbFeiZn20 (a = 1411.1(1) pm ), YRu2Zn20 (a = 1422.6(1) pm ), DyRu2Zn20 (a = 1422.1(1) pm), GdCo2Zn20 (a = 1406.0(1) pm ), DyRh2Zn20 (a = 1418.2(1) pm ), and TmNi2Zn20 (a= 1401.6(1) pm) to conventional residuals varying betw een R = 0.011 and R - 0.024. The com pounds have a tendency for tw inning, thus m im icking hexagonal sym metry, with the cubic [111] axis as the axis w ith the pseudohexagonal symmetry. M inor inconsistencies in the cell volum es of these com pounds indicate slight deviations from the ideal com position. N evertheless, the five atom ic sites of this structure w ere found to be fully occupied w ithin the error lim its w ith the exception of one zinc site of TmNi2Zn20. The coordination for the site of the rare earth atom s is a Frank-K asper polyhedron with coordination num ber (CN) 16. The transition metal atom s occupy a site w ith icosahedral zinc coordination (CN 12). Two of the three zinc sites are in pentagonal prism atic coordination of zinc atom s, capped by rare earth and/or transition metal atom s (CN 12), w hile the third zinc site has 12 zinc neighbors form ing a hexagonal prism , w hich is capped by tw o rare earth atom s (CN 14).