KCo(H₂O)₂BP₂O₈·0.48H₂O and K_0.17Ca_0.42Co(H₂O)₂BP₂O₈·H₂O: two cobalt borophosphates with helical ribbons and disordered (K,Ca)/H₂O schemes

The two investigated compounds have similar [CoBP₂O₈]⁻ anionic frameworks but differ in their (K,Ca)/H₂O disorder schemes. In the structure of the pure potassium borophosphate, the solvent water mol­ecules and a fraction of the alkali cations are located within the helical channels.