There are five special characters that you should not use as values within your XML data. These special characters can be replaced with a string of characters known as Entity References.

The characters are the less-than and greater-than signs (because XML would not know where the elements start and finish), the apostrophe / single quote, the double-quote, and the ampersand (because the entity references start with an ampersand).

All entity references start with an ampersand and finish with a semi-colon.

The below table lists the characters and the entity references in place of those characters.