Theoretical inorganic chemistry What class of compounds?
Hello! It is interesting to which class of inorganic substances can be attributed aluminosilicates - salts or mixed oxides? Also, what can you say about similar compounds of metals - chromites, aluminates, ferrites, perovskites and the like
Aluminosilicates can be considered as salts, since they are a salt of the corresponding acid, in which hydrogen atoms are replaced by metal cations.
@max I would not support your answer because the crystal lattice of all named compounds consists of oxide anions O2- and individual cations like Al3+ etc. You would be able to find the anions of acids like TiO32- in CaTiO3. So, all of them are oxide minerals. They differ from salts, like Na2SO4 as in sulfate the sulfate anion is present as single unit an not separate sulphur cation and oxide anions.
Aluminosilicates are compounds formed by oxides of aluminum, silicon, alkaline and alkaline earth metals.
It was found that the main "building block" of these compounds is an atom of silicon or aluminum surrounded by four oxygen atoms - silicon (aluminum)oxygen tetrahedron SiO4(AlO4). The diversity of aluminosilicates is explained by different ways of connecting these tetrahedra, which are usually joined by vertices to form Si-O-Si and Si-O-Al bonds. Even at the time Vernadsky rejected the idea that aluminosilicates are salts of silicic acids. In his opinion, aluminosilicates are derivatives of complex aluminosilicate radicals, "kaolin nuclei".
As for chromites, aluminates, ferrites, perovskites, etc., these are also complex oxides. After all, all these compounds, including aluminosilicates, are non-stoichiometric compounds, their compositions vary widely.
Aluminosilicates are frame oxosilicates in which a part of silicon atoms is replaced by trivalent Al. Aluminosilicates can be considered as salts of aluminosilicon acids, as well as mixed oxides, which in nature include a large group of minerals of the silicate class. It is known that mixed oxides are called salt-like, because they are salts in structure and properties. Therefore, aluminosilicates can be represented as complex anions [AlSiO4]-, [AlSi2O6]-, [AlSi4O10]-, [Al2Si3O10]2- cations and (usually K+ and Na+) and as mixed oxides
Me2/nO ·Al2O3 · xSiO2 · yH2O.
@damiryagudin thank you, that is, aluminosilicates can be attributed to both oxides and salts?
@argentum Note: For example, for reactions involving aluminosilicates, aluminosilicates are usually presented as complex anions and cations. However, most often aluminosilicates are presented in the form of mixed oxides, showing, for example, the number of moles of silicon oxide related to the number of moles of aluminum oxide. This is typical for the classification of frame aluminosilicates - zeolites.
Are compounds like NaAlO2,Na2ZnO2, K2SnO2, K2TiO3 are salts or mixed oxides?
These compounds, as well as aluminosilicates, are salts. However, they can be represented both in the form of corresponding cations and anions, and in the form of mixed oxides. I spoke about mixed oxides earlier.
By the way, the question arose whether aluminosilicates in the melt are electrolytes?
Solid state electrolytes are also dielectrics