Synthesis and crystal structure of layered molybdate NH₄Co₂OH (MoO₄)₂?H₂O

A new compound NH4Co2OH(MoO4)(2)center dot H2O was prepared by precipitation of aqueous solutions of cobalt nitrate and ammonium heptamolybdate at pH = 7.5. The crystal structure was identified by X-ray powder diffraction (XRPD) and Rietveld refinement as a known polymorph of layered molybdates (Phi(y)) with general formula AT(2)OH(MoO4)center dot H2O (A = NH4+, Na+, K+ and T = Zn2+, Co2+, Cu2+, Ni2+) and refined from a model based on that structure. The lattice parameters were refined with R-3 space group (148) alpha = 6.1014(2) angstrom, b = 6.1014(2) angstrom, c = 21.826(1) angstrom, alpha = 90 degrees, beta = 90 degrees, and gamma = 120 degrees. (c) The Author(s), 2023. Published by Cambridge University Press on behalf of International Centre for Diffraction Data.