Model structures for C-(A)-S-H(I)

C-(A)-S-H(I) is a structurally imperfect form of 14 Å tobermorite that is studied extensively as a model for the main binding phase in concrete. Crystal-chemically plausible structures are developed that account for a wide range of experimental observations, including variations in calcium to silicon ratio, water to silicon ratio, (alumino)silicate anion structure and layer spacing.