The La-poor part of the ternary La–Ni–Si system has been explored leading to the discovery and structural characterization of four new polar intermetallic compounds. LaNi₅Si₂ [BaAu₅Ga₂ type, oP64, space group Pnma, a = 7.8223(7) Å, b = 6.3894(6) Å, c = 17.843(2) Å, V = 891.8(2) ų, Z = 8] features a diamond (lonsdaleite)-like homoatomic Ni framework and is the first Ni representative of a larger family of compounds typically formed by aurides. La₂Ni₈Si₃ [Eu₂Ni₈Si₃ type, tP52, P4₂/nmc, a = 10.0278(3) Å, c = 7.5047(4) Å, V = 754.65(6) ų, Z = 4] is characterized by homoatomic Ni₄ tetrahedra and rectangles. LaNi₅Si₃ [SrNi₅P₃ type, oS36, Cmcm, a = 3.722(2) Å, b = 11.759(5) Å, c = 11.622(3) Å, V = 508.7(3) ų, Z = 4] is governed by extensive heteroatomic bonding and characterized by homopolyhedral packing. La₃Ni₄Si₂ [Ce₃Ni₄Si₂ type, mC36, C2/c, a = 15.819(1) Å, b = 6.0068(5) Å, c = 7.4918(6) Å, β = 103.163(5)°, V = 693.17(10) ų, Z = 4] is a new member of homologous series that includes La₃Ni₃Si₂ and La₃Ni_3.5Si₂. We conclude that the similar radii and electronegativities of Ni and Si are the reason for the incredible diversity of compositions and structures in this system.

中文翻译：

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La-Ni-Si：镶有钻石的金矿


已经探索了三元 La-Ni-Si 系统的 La-poor 部分，从而发现了四种新的极性金属间化合物并进行了结构表征。LaNi₅Si₂ [BaAu₅Ga₂ 型，oP64，空间群 Pnma，a = 7.8223 （7） Å，b = 6.3894（6） Å，c = 17.843（2） Å，V = 891.8（2） Å^3，Z = 8] 具有菱形（朗斯代尔石 ）状同原子 Ni 框架，是通常由金刚石形成的较大化合物家族中第一个代表的 Ni。La₂Ni₈Si₃ [Eu₂Ni₈Si₃ 型，tP52，P 4₂/nmc，a = 10.0278（3） Å，c = 7.5047（4） Å，V = 754.65（6） Å^3，Z = 4] 以同原子 Ni₄ 四面体和矩形为特征 。LaNi₅Si₃ [SrNi₅P₃ 型，oS36，Cmcm，a = 3.722（2 ） Å，b = 11.759（5） Å，c = 11.622（3） Å，V = 508.7（3） Å^3，Z = 4] 由广泛的异原子键控制，并以同多 面体堆积为特征。La₃Ni₄Si₂ [Ce₃Ni₄Si₂ 型，mC36，C 2/c，a = 15.819（1） Å，b = 6.0068（5） Å，c = 7.4918（6） Å，β = 103.163（5）°，V = 693.17（10） Å^3，Z = 4] 是同源系列的新成员，包括 La₃Ni₃Si ₂ 和 La₃Ni_3。5Si₂.我们得出结论，Ni 和 Si 相似的半径和电负性是该系统中成分和结构令人难以置信的多样性的原因。