A.W. Kolsi

Crystal structure of mixed rubidium–ammonium hydrogen sulfate Rb0.7(NH4)0.3HSO4 at room temperature

The structure of Rb0.7(NH4)0.3HSO4 has been determined by X-ray analysis. The mixed compound crystallizes in the monoclinic space group P21/n with unit cell parameters a = 14.374(6) Å, b = 4.618(6) Å, c = 14.412(2) Å, β = 118.03(2)°, V = 844.4(4) Å3, and Dcal = 1.536 g cm−3 for Z = 8. The mixed compound Rb0.7(NH4)0.3HSO4 is a chain-based structure. The Rb+ and NH4+ cations are intercalated between chains, formed of HSO4- groups linked with OH⋯O hydrogen-bonding. Rb0.7(NH4)0.3HSO4 presents a new type of structural arrangement different from those of pure RbHSO4 and NH4HSO4.

The solid solution Na0.39(NH4)1.61SO4·Te(OH)6

The title compound, sodium ammonium sulfate–telluric acid (1/1), Na0.39(NH4)1.61SO4·Te(OH)6, is isostructural with other solid solutions in the series M 1−x(NH4)xSO4·Te(OH)6, where ammonium is partially replaced with an alkali metal (M = K, Rb or Cs). The structure is composed of planes of Te(OH)6 octahedra alternating with planes of SO4 tetrahedra. The Na+/NH4 + cations are statistically distributed over the same position and are located between the planes. The structure is stabilized by O—H⋯O and N—H⋯O hydrogen bonds between the telluric acid adducts and the O atoms of sulfate groups, and between the ammonium cations and O atoms, respectively. Both Te atoms lie on centres of symmetry.