Here is one way to prepare a pressure vs. composition V-L equilibrium diagram. Is it easy to do this in Excel 2007 (using a 'double' horizontal axis)? (See Ch. 26 in Metiu's PChem Thermo textbook, Table 26.3, 1=CS2, 2=benzene, T=298 K.)

p = {117.40, 144.00, 177.80, 220.10, 251.10, 298.70, 323.10, 337.40, 
          351.20, 356.20};
x1 = {0.0581,  .1286,  .2337,  .3698,  .5014,  .6998,  .8176,  .8847,  .9532,  .9789};
y1 = { .2376,  .4180,  .5765,  .7114,  .7861,  .8825,  .9257,  .9526,  .9798,  .9902};

Let's display the data in a table.

TableForm[
      Transpose[{p, y1, 
          x1}], 
TableHeadings -> {None, {"p \
(torr)", "y1", "x1"}}]

Let's now make a constant temperature phase diagram with these data.

Needs["Graphics`MultipleListPlot`"]

bubble = Transpose[{ x1, p}];
dew = Transpose[{y1, p}];
MultipleListPlot[dew, bubble , 
        SymbolShape -> {MakeSymbol[RegularPolygon[5, 4]], 
            MakeSymbol[
              RegularPolygon[4, 
                4]]}, 
AxesLabel -> {"x1 or y1", "\
p (torr)"}, PlotRange -> {0, 300}, 
        PlotJoined -> True];