Firstly, I want the legend for Series 1 to be CO2. So I’ll start by typing CO into a cell.
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Go to the Insert Tab and select Symbols.
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Use the dropdown list to find Superscripts and Subscripts.
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This is where most of the superscript and subscript numbers are. I will select the subscript 2 and then click Insert.
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The superscript 1, 2 & 3 are in a different place, if you want these numbers, scroll back up to the top and you will see them in the Latin-1 Supplement section.
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Now, we have CO2 in a cell, right click on the chart and click Select Data…
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Then we will Edit the series.
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Change the series name so that it is linked to the cell with CO2 in it. Then click OK twice.
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Now, for Series 1, there is CO2 with a subscript 2, in the legend of the chart.
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