Rb₂Ni(SO₄)₂·6H₂O (RbNSH) and Cs₂Ni(SO₄)₂·6H₂O (CsNSH) crystals belong to the nickel Tutton salts.

The large single crystals of Rb₂Ni(SO₄)₂·6H₂O (RbNSH) and Cs₂Ni(SO₄)₂·6H₂O (CsNSH) were grown. Some properties of these crystals were studied such as their structure, transmission spectra, thermal stability.

We determined the solubility curves of these salts in preparation for the crystal growth process. Both crystals were grown from low temperature solutions: by temperature decrease and by the solvent-evaporation techniques. Due to different solubility the normal growth rates were 0.2-0.4 mm/day for RbNSH and 0.5-2.0 mm/day for CsNSH depending on the crystal faces.

The RbNSH structure was refined and CsNSH structure was determined.  RbNSH and CsNSH crystals belong to monoclinic sp.gr. P2₁/c and form isostructural series with ANSH and KNSH.

Transmission spectra demonstrate rather high transparence in UV band (220-320 nm) that makes them possible for application as UV-filters.

The thermogravimetric measurements were made for both crystals. It was shown that the process of the single crystal dehydratation starts at temperatures 107 ºC for CsNSH and 110 ºC for RbNSH (the sample heating rate was 5 K/min). So these crystals are more thermal stable than well known α-NSH, ANSH and KNSH.

For CsNSH crystal the microhardness of (010), (001) and (100) plates was studied. The distinction in the hardness of different faces indicates the presence of anisotropy of the second kind in these crystals with the anisotropy coefficient k₁=1.4.

The internal defect structure of RNSH and CsNSH crystals was studied by X-ray topography. It was shown that growing CsNSH crystals by the solvent-evaporation method preferable.

Due to their good optical and thermogravimetric properties both crystals could be used as material for UV filters

• Legal notice:
  

  Copyright (c) Pielaszek Research, all rights reserved.
  The above materials, including auxiliary resources, are subject to Publisher's copyright and the Author(s) intellectual rights. Without limiting Author(s) rights under respective Copyright Transfer Agreement, no part of the above documents may be reproduced without the express written permission of Pielaszek Research, the Publisher. Express permission from the Author(s) is required to use the above materials for academic purposes, such as lectures or scientific presentations.
  In every case, proper references including Author(s) name(s) and URL of this webpage: https://science24.com/paper/29747 must be provided.

1. Revision of one-dimensional analytical models of effective segregation coefficient and their application for recovering the crystal growth conditions of space grown GaSb:Te
2. Simplified numerical approach for estimation of effective segregation coefficient at the melt/crystal interface
3. Peculiarities of the growth and structure formation of new KDP:Al₂O₃·nH₂O composite material
4. The study of temperature equilibrium of KDP, ADP crystals and solutions from their magnetic treatment