What is the bond order in Connection Tablefiles and how is its value determined?

What is the bond order in Connection Table files and how is its value determined?

Double bonds are bit encoded using a bitmask (so 13 = 8 + 4 + 1). The values of the bits are as follows:

• 1 The second line is on the left (looking from the first atom to the second)
• 2 The two lines are centered
• 8 (A modifier to the previous two values, indicating that the user specifically set the positioning. Without this bit, ChemDraw calculated the positioning automatically)
• 4 A double bond with one dashed and one solid line
• 16 A double bond with one bold and one solid line
• 32 A crossed bond.
• 64 A double bond with two dashed lines

The default value, 0, indicates a normal (two solid lines) double bond, with the second line on the right (looking from the first atom to the second).

Using the example above, 13 (= 8 + 4 + 1) means a double bond with one dashed and one solid line (4), where the user specifically wants (8) the second line to be on the left (1).