Herein, the synthesis of Co
2Si
5N
8 nitridosilicate from
α‐Ca
2Si
5N
8 by ion exchange is described. The monoclinic
structure (space group
Cc) is compared with those of the related nitridosilicates Ca
2Si
5N
8 and Fe
2Si
5N
8 its magnetic properties are profoundly investigated. Most interestingly, polycrystalline Co
2Si
5...