Processes for treating coral and coating an object

A process for coating an object with a divalent metal phosphate, the process comprising the steps of:

• (a) preparing a sol containing a divalent metal phosphonate complex wherein a divalent metal is coordinated to a phosphonate compound according to formula (1)
• R—C(O)—O—P(O)R1—O—C(O)—.R2 (1)
• wherein R, R1 and R2, which may be the same or different, are selected from the group consisting of hydrogen, substituted alkyl groups and unsubstituted alkyl groups;
• and
• (b) dipping the object into the sol;
• (c) heating the dipped object in order to remove any solvent;
• and
• (d) firing the heated object to allow conversion of the divalent metal phosphonate complex into the divalent metal phosphate.