Argon is a VIII-group element, a noble gas at ambient
pressure. Ar is used in high pressure experiments with
diamond anvil cells as a pressure transmitting medium.
The knowledge of the physical properties of argon,
especially the p-T phase diagram, i.e. thermodynamic
eqillibrium parameters of the solid-liquid-gas phase
transitions are very important to understand the process of
DAC loading with Ar.
The p-T phase diagram of argon is, to our knowledge,
available in the literature only in the numerical form.
In this communication we present the drawing of the Ar
phase diagram explicitly. We discuss the parameters of the
diagram in the vicinity of the triple point as crucial for