Quote Originally Posted by Relayer View Post
Mark, Sodium metaborate 4 mol == NaBO24H2O ?
I'll answer instead of Mark: Photo Formulary sells sodium metaborate which according to their MSDS is sodium metaborate 4 mol. This MSDS lists the formula NaBO22H2O [Na2B2O44H2O]

Likewise there is a reference on http://www.borax.com which lists both 4 mol (NaBO22H2O) and 8 mol (NaBO24H2O) sodium metaborate. So for all practical purposes I would assume that Mark means the 4 mol compounds as defined by these references: NaBO22H2O

The confusing names seem to come from the double compounds Na2B2O44H2O and Na2B2O48H2O