Hexafluorosilicates of sarcosine

► Large single crystals of 3 species in the system sarcosine-H2SiF6-H2O were grown. ► Crystal structure, vibrational spectra and tensors of thermal expansion are given. ► 3Sar·H2SiF6·2H2O has a phase transition at 180 K to a non-centrosymmetric structure.