I would like to explain my question with the following illustrative situation. In general, when we apply the high-pressure and high temperature to the solid materials, the solid melts and it goes into the liquid state. What will be nature of the structure of the liquid state?
In precise, I want to give one example. I take some solid materials like BiSe, Bi2Se3, Bi2Se5, Bi3Se7, Bi4Se10e tc. In all these compounds, the basic elemental unit is two, i.e., Bi and Se, but the composition is different.
If I apply high-pressure and high temperature, all these solid materials melt and goes into liquid state.
Does all liquid’s structure and nature same irrespective of the starting composition? [Or] Is it depends on the initial composition? Please let me know.
Your valuable explanation, suggestion, and guidance will be very useful to our research works. Thank you very much in advance.
The answer depends very much on the chemical properties of your compounds. Bi2Se3 contains Bi3+ ions, whereas Bi2Se5 contains Bi5+ ions. The ions retain their oxydation states when the material melts. Molten Bi2Se3 is therefore not the same as Bi2Se5 with some added Se.
On the other hand, in materials like Na2S2, Na2S3, … the sulfur atoms form chains, and in the molten state these chains can exchange atoms. Here the liquid would not preserve the information from which pure salts it was created.
Thank you Ulrich Deiters for your answer and valuable time. It helps. I have one more question related to this.
Let’s take the case of phosphorous. It has several allotropes with unique structures and properties. For instance, White Phosphorus, Red Phosphorus, Black Phosphorus, Violet Phosphorus. Let’s assume that, I have taken all these Phosphorous systems and applied the high-pressure and high-temperature. All will goes into liquid state. Will these liquids be the same or different in terms of structure and nature? If possible, could you please clarify this? Thanks.
A nasty question! White phosphorus consists of P4 molecules, and it has a normal melting point. Red and blacks phosphorus are polymeric or crystalline, and the P atoms form large structures. The “melting” of these modifications is, in fact, a chemical reaction that produces P4. Hence you cannot conclude from the presence of P4 molecules whether the original solid was white, red, or black.
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