Error with the for loop code. The loop is not overwriting the values in the cloumn

I want to add a new column consisting different colors to my data frame. So that I can use that column in the arg col while plotting the points of that variable.

I want to assign same color for a values falling in same range and different colors for those falling in different range.

For example, I have a certain dataset consisting of following values:

> CN 

A    X
1    0.05
2    0.09
3    NA
4    0.12
5    0.35
6    0.21
7    NA
8    0.01
9    0.14
10   0.32
11   0.43
12   0.19

I would like to add a separate column (Col) to my dataframe CN

> CN$Col <= "white" 

Its a success in creating a new column. I would like to assign different colors to each of these values. And assign either white or a transparent color for NA values. i.e

<0.05      -- red
0.05 - 0.1 -- orange
0.1  - 0.2 -- yellow
0.2  - 0.3 -- green
0.3  - 0.4 -- darkviolet
0.4  - 0.5 -- blue

Here is the code I have written

CN$Col <- "white"

for (i in 1:length(CN)) {
d <- is.na(CN$X[i])
 if (d == "FALSE") {
   if (CN$X[i] <= 0.05)
     CN$Col[i] <- "red"
   else if (CN$X[i] <= 0.1 && CN$X[i] > 0.05)
     CN$Col[i] <= "orange"
   else if (CN$X[i] <= 0.2 && CN$X[i] > 0.1)
     CN$Col[i] <- "yellow"
   else if (CN$X[i] <= 0.3 && CN$X[i] > 0.2)
     CN$Col[i] <- "green"
   else if (CN$X[i] <= 0.4 && CN$X[i] > 0.3)
     CN$Col[i] <- "darkviolet"
   else if (CN$X[i] <= 0.5 && CN$X[i] > 0.4)
     CN$Col[i] <- "blue"
 }
else
CN$Col[i] <- rgb(0, 0 , 0, alpha = 0) # rgb command can be replaced with color white
}

This code does not overwrite the white I have fed to the column earlier.

Thanks in advance.