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The image appears to be a part of a chemistry text, possibly written in Russian, and includes a chemical equation:

\[ \text{PCl}_5 \rightarrow X \text{K}_3\text{PO}_4 - \text{Ca}_3(\text{PO}_4)_2 \]

If you're looking for help with this equation or the context, could you provide more details or clarify what kind of assistance you need?