Materials Data on Mg5Si6 by Materials Project

Mg5Si6 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are ten inequivalent Mg sites. In the first Mg site, Mg is bonded in a 4-coordinate geometry to five Si atoms. There are a spread of Mg–Si bond distances ranging from 2.67–2.96 Å. In the second Mg site, Mg is bonded in a rectangular see-saw-like geometry to four Si atoms. There are a spread of Mg–Si bond distances ranging from 2.78–2.81 Å. In the third Mg site, Mg is bonded in a 8-coordinate geometry to eight Si atoms. There are a spread of Mg–Si bond distances ranging from 2.76–3.03 Å. In the fourth Mg site, Mg is bonded in a 6-coordinate geometry to six Si atoms. There are a spread of Mg–Si bond distances ranging from 2.77–3.19 Å. In the fifth Mg site, Mg is bonded in a 2-coordinate geometry to eight Si atoms. There are a spread of Mg–Si bond distances ranging from 2.85–3.14 Å. In the sixth Mg site, Mg is bonded in a 7-coordinate geometry to eight Si atoms. There are a spread of Mg–Si bond distances ranging from 2.72–3.15 Å. In the seventh Mg site, Mg is bonded in a 7-coordinate geometry to seven Si atoms. There are a spread of Mg–Si bond distances ranging from 2.63–3.04 Å. In the eighth Mg site, Mg is bonded in a 8-coordinate geometry to eight Si atoms. There are a spread of Mg–Si bond distances ranging from 2.82–3.04 Å. In the ninth Mg site, Mg is bonded in a 7-coordinate geometry to seven Si atoms. There are a spread of Mg–Si bond distances ranging from 2.85–3.12 Å. In the tenth Mg site, Mg is bonded to eight Si atoms to form distorted face-sharing MgSi8 tetrahedra. There are a spread of Mg–Si bond distances ranging from 2.72–3.27 Å. There are twelve inequivalent Si sites. In the first Si site, Si is bonded in a 8-coordinate geometry to six Mg and two equivalent Si atoms. There are one shorter (2.50 Å) and one longer (2.53 Å) Si–Si bond lengths. In the second Si site, Si is bonded in a 9-coordinate geometry to eight Mg and one Si atom. The Si–Si bond length is 2.43 Å. In the third Si site, Si is bonded in a 9-coordinate geometry to seven Mg and two Si atoms. There are one shorter (2.41 Å) and one longer (2.42 Å) Si–Si bond lengths. In the fourth Si site, Si is bonded in a 9-coordinate geometry to seven Mg and two Si atoms. The Si–Si bond length is 2.44 Å. In the fifth Si site, Si is bonded in a 10-coordinate geometry to six Mg and four Si atoms. There are one shorter (2.45 Å) and one longer (2.47 Å) Si–Si bond lengths. In the sixth Si site, Si is bonded in a 1-coordinate geometry to six Mg and three Si atoms. There are a spread of Si–Si bond distances ranging from 2.46–2.51 Å. In the seventh Si site, Si is bonded in a 9-coordinate geometry to six Mg and three Si atoms. There are a spread of Si–Si bond distances ranging from 2.50–2.55 Å. In the eighth Si site, Si is bonded in a 9-coordinate geometry to six Mg and three Si atoms. There are one shorter (2.65 Å) and one longer (2.67 Å) Si–Si bond lengths. In the ninth Si site, Si is bonded in a 8-coordinate geometry to four Mg and four Si atoms. There are one shorter (2.55 Å) and one longer (2.60 Å) Si–Si bond lengths. In the tenth Si site, Si is bonded in a 9-coordinate geometry to five Mg and four Si atoms. In the eleventh Si site, Si is bonded in a 7-coordinate geometry to three Mg and four Si atoms. In the twelfth Si site, Si is bonded in a 7-coordinate geometry to five Mg and four Si atoms.

Mg₅Si₆结晶于三斜晶系P1空间群，其晶体结构为三维骨架结构。体系中存在10个不等价的镁（Mg）位点：
在第一个镁位点中，Mg以四配位几何构型与5个硅（Si）原子成键，Mg-Si键的键长分布范围为2.67~2.96 Å。
在第二个镁位点中，Mg以矩形跷跷板状几何构型与4个硅（Si）原子成键，Mg-Si键键长分布范围为2.78~2.81 Å。
在第三个镁位点中，Mg以八配位几何构型与8个硅（Si）原子成键，Mg-Si键键长分布范围为2.76~3.03 Å。
在第四个镁位点中，Mg以六配位几何构型与6个硅（Si）原子成键，Mg-Si键键长分布范围为2.77~3.19 Å。
在第五个镁位点中，Mg以二配位几何构型与8个硅（Si）原子成键，Mg-Si键键长分布范围为2.85~3.14 Å。
在第六个镁位点中，Mg以七配位几何构型与8个硅（Si）原子成键，Mg-Si键键长分布范围为2.72~3.15 Å。
在第七个镁位点中，Mg以七配位几何构型与7个硅（Si）原子成键，Mg-Si键键长分布范围为2.63~3.04 Å。
在第八个镁位点中，Mg以八配位几何构型与8个硅（Si）原子成键，形成畸变共面的MgSi₈多面体单元，Mg-Si键键长分布范围为2.82~3.04 Å。
在第九个镁位点中，Mg以七配位几何构型与7个硅（Si）原子成键，Mg-Si键键长分布范围为2.85~3.12 Å。
在第十个镁位点中，Mg与8个硅（Si）原子成键，形成畸变共面的MgSi₈多面体单元，Mg-Si键键长分布范围为2.72~3.27 Å。
体系中同时存在12个不等价的硅（Si）位点：
在第一个硅位点中，Si以八配位几何构型与6个镁（Mg）原子及2个等价的硅（Si）原子成键，存在一条较短（2.50 Å）和一条较长（2.53 Å）的Si-Si键长。
在第二个硅位点中，Si以九配位几何构型与8个镁（Mg）原子及1个硅（Si）原子成键，Si-Si键长为2.43 Å。
在第三个硅位点中，Si以九配位几何构型与7个镁（Mg）原子及2个硅（Si）原子成键，存在一条较短（2.41 Å）和一条较长（2.42 Å）的Si-Si键长。
在第四个硅位点中，Si以九配位几何构型与7个镁（Mg）原子及2个硅（Si）原子成键，Si-Si键长为2.44 Å。
在第五个硅位点中，Si以十配位几何构型与6个镁（Mg）原子及4个硅（Si）原子成键，存在一条较短（2.45 Å）和一条较长（2.47 Å）的Si-Si键长。
在第六个硅位点中，Si以一配位几何构型与6个镁（Mg）原子及3个硅（Si）原子成键，Si-Si键键长分布范围为2.46~2.51 Å。
在第七个硅位点中，Si以九配位几何构型与6个镁（Mg）原子及3个硅（Si）原子成键，Si-Si键键长分布范围为2.50~2.55 Å。
在第八个硅位点中，Si以九配位几何构型与6个镁（Mg）原子及3个硅（Si）原子成键，存在一条较短（2.65 Å）和一条较长（2.67 Å）的Si-Si键长。
在第九个硅位点中，Si以八配位几何构型与4个镁（Mg）原子及4个硅（Si）原子成键，存在一条较短（2.55 Å）和一条较长（2.60 Å）的Si-Si键长。
在第十个硅位点中，Si以九配位几何构型与5个镁（Mg）原子及4个硅（Si）原子成键。
在第十一个硅位点中，Si以七配位几何构型与3个镁（Mg）原子及4个硅（Si）原子成键。
在第十二个硅位点中，Si以七配位几何构型与5个镁（Mg）原子及4个硅（Si）原子成键。