Structural and thermal properties of Na 2 Mn(SO 4 ) 2 ·4H 2 O and Na 2 Ni(SO 4 ) 2 ·10H 2 O

Hamdi Ben Yahia, Alaa Alkhateeb, Rachid Essehli
2020 RSC Advances  
The title compounds were prepared a wet chemistry route and their crystal structures were determined from single crystal X-ray diffraction data. Na 2 Mn(SO 4 ) 2 ·4H 2 O crystallizes with a monoclinic symmetry, space group 2 1 / , with = 5.5415(2), = 8.3447(3), = 11.2281(3) Å, = 100.172(1)°, = 511.05(3) Å 3 and = 2. Na 2 Ni(SO 4 ) 2 ·10H 2 O also crystallizes with a monoclinic symmetry, space group 2 1 / , with = 12.5050(8), = 6.4812(4), = 10.0210(6) Å, = 106.138(2)°, = 780.17(8) Å 3 and = 2.
more » ... 7(8) Å 3 and = 2. Na 2 Mn(SO 4 ) 2 ·4H 2 O is a new member of the blödite family of compounds, whereas Na 2 Ni(SO 4 ) 2 ·10H 2 O is isostructural with Na 2 Mg(SO 4 ) 2 ·10H 2 O. The structure of Na 2 Mn(SO 4 ) 2 ·4H 2 O is built up of [Mn(SO 4 ) 2 (H 2 O) 4 ] 2− building blocks connected through moderate O–H⋯O hydrogen bonds with the sodium atoms occupying the large tunnels along the axis and the manganese atom lying on an inversion center, whereas the structure of Na 2 Ni(SO 4 ) 2 ·10H 2 O is built up of [Ni(H 2 O) 6 ] 2+ and [Na 2 (SO 4 ) 2 (H 2 O) 4 ] 2− layers. These layers which are parallel to the (100) plane are interconnected through moderate O–H⋯O hydrogen bonds. The thermal gravimetric- and the powder X-ray diffraction-analyzes showed that only the nickel phase was almost pure. At a temperature above 300 °C, all the water molecules evaporated and a structural phase transition from 2 1 / -Na 2 Ni(SO 4 ) 2 ·10H 2 O to 2/ -Na 2 Ni(SO 4 ) 2 was observed. [...]
doi:10.1039/d0ra00301h fatcat:onaua377c5g2nkrcwsjpapkm7i