Could my trusty old data-book have yet Another error in it?

 

it clearly states that Mg3(PO4)2.4H2O is a Blue monoclinic crystal, since I like "collecting" colored crystals I put a chunk of Mg into some Phoshoric acid to make some.

It`s Not blue.

in fact if anything it`s a clear to grey liquid without even the slightest hint of blue with a white paper test.

I`ve tried to google for it, and there`s no mention of blue there either, anyone have any ideas what it could be on about? or is it just another error (like the MP of NaHSO4 being 6588 kelvin!).

No, if pure, it is white. In practice it may be very light grey. Just as with calcium phosphate.

 

Magnesium salts usually are white or off-white, simply because the Mg(2+) ion is colorless. If color is imparted to magnesium salts then the anion gives the color to the salt.

Mg3(PO4)2.5H2O is a white powder

 

sources:

http://composite.about.com/library/glossary/m/bldef-m3191.htm

http://www.jostchemical.com/chemicals/2565.html

http://physchem.ox.ac.uk/MSDS/MA/magnesium_phosphate_dibasic_trihydrate.html

 

Hydrated magnesium phosphate carbonate hydroxide is blue, which is possibly where the book went wrong, maybe.

 

[edit] woelen's post wasn't there 2mins ago when I loaded the page.

well I thought it was strange myself (that`s why I tried it), all the Mg salts I`ve encountered are as you say, either white or clear.

 

I`ll chalk it up to yet Another error in this book

 

the 1`st one I ever noticed in it was the BP of H2O2 being 323 kelvin, Grrr...

 

Thanx Both