Hi,

Make an XY-scatter plot with the following data (Series 1, shown as x,
y-pairs); this forms the triangular boundary. Format the line to suit to
your taste. In €œChart Options€�/ €œAxes€� Tab, uncheck X- and Y- axes to hide
them. Similarly get rid of the borders of the plot and chart areas, and
resize the areas to get a triangle that looks €˜equilateral on the screen (!)

Series 1:
0.0, 0.00
0.5, 0.86603
1.0, 0.00
0.0, 0.00

Add 5 more series to the above graph with the following data (these form the
grids; format the lines appropriately)

Series 2:
0.05, 0.086603
0.10, 0.00
0.55, 0.77942
0.45, 0.77942
0.90, 0.00
0.95, 0.086603
0.05, 0.086603
Series 3:
0.10, 0.17321
0.20, 0.00
0.60, 0.69282
0.40, 0.69282
0.80, 0.00
0.90, 0.17321
0.10, 0.17321
Series 4:
0.15, 0.25981
0.30, 0.00
0.65, 0.60622
0.35, 0.60622
0.70, 0.00
0.85, 0.25981
0.15, 0.25981
Series 5:
0.20, 0.34641
0.40, 0.00
0.70, 0.51962
0.30, 0.51962
0.60, 0.00
0.80, 0.34641
0.20, 0.34641
Series 6:
0.25, 0.43301
0.50, 0.00
0.75, 0.43301
0.25, 0.43301

Plotting the data:

Please note that the above approach assumes that the compositions of ternary
mixtures are expressed in terms of the fraction (and not percentage) of
components A and B (i.e., fA and fB); so fC = 1-fA-fB.
In say A21€¦.. and B21 €¦.., enter fA and fB respectively. In C21 enter the
formula = 1-A21-B21 (This column is only for completeness and is not really
necessary for the plot. However, if you do create this column, you could
simplify the formulas below by replacing €œ(1-A21-B21)€� with €œC21€�).

In D21 enter the formula, =B21+(1-A21-B21)*COS(PI()/3) [x-value of the
data point]
In E21 enter the formula, =(1-A21-B21)*SIN(PI()/3) [y-value of the data
point]

Auto-fill the formulas down to the last row.

Add a series to the blank ternary plot area you have already created, with
E21:Elastrow (y-range) vs D21:Dlastrow (x-range).

The left-hand-side bottom, right-hand-side bottom and the top corners of the
triangle correspond to pure A, B, and C respectively.

Regards,
B. R. Ramachandran


"Frank Martin" wrote:

I have Excel2003 and I need some way to form triangular/ternary charts.

Is there any way, or is there some plug-in available?

Please help, Frank