Melting ice: Group relations and relationships between numbers of independent variables and various constants in its parametric descriptions

It is shown that direct group cosubjection of symmetries of neighboring crystalline phases of water along the melting and sublimation curves in the pT phase diagram is observed only for ices V and VI. Those relationships between numbers N V of independent variable parameters and numbers N C of unequal constants in the parametric description of neighboring phases at their interfaces, which are needed for transitions to take place, are fulfilled inmost cases. Correlation is established between the absolute values of entropy variation |Δ S | and the absolute values |Δ N C | and |Δ N V | at the transitions through the boundaries of phase regions.