The cyanamide and carbodiimide anions are complex nitrogen-derived one-dimensional species of the type NCN2− (hence, resembling O2− but more covalently bonding) that form a huge number of salt-like phases with a variety of metal cations stemming from the whole Periodic Table. Depending on the coloring (binary, ternary and quaternary salts are known), the cationic size and charge as well as covalent contributions, different distortion (tilting in particular) and/or vacancy ordering variants of cyanamides/carbodiimides occur. Herein we summarize those cyanamide/carbodiimide structures that derive from the aristotype NiAs. The crystal chemistry is discussed on the basis of group-subgroup schemes (Bärnighausen trees).

中文翻译：

---

NiAs 衍生的氰胺（碳二亚胺）结构——群论观点

氰胺和碳二亚胺阴离子是 NCN 型的复杂氮衍生一维物种2−（因此，类似于 O2−但更多的是共价键合），它们与来自整个元素周期表的各种金属阳离子形成大量的盐状相。根据颜色（二元、三元和季盐是已知的）、阳离子大小和电荷以及共价贡献，氰胺/碳二亚胺的不同变形（特别是倾斜）和/或空位排序变体发生。在这里，我们总结了那些源自亚里斯型 NiAs 的氰胺/碳二亚胺结构。晶体化学是在群-子群方案（Bärnighausen 树）的基础上讨论的。