Talk:Manganese(II) carbonate

Contradiction

In the chembox and the picture, it says that manganese(II) carbonate is a brown solid. In the "Production and Uses" paragaph, it says that it is faintly pink solid. So what is it? I tried adding sodium carbonate solution to manganese(II) sulfate solution, and got a faintly pink precipitate (which should be manganese(II) carbonate). So is manganese(II) carbonate brown or faintly pink? YOSF0113 (talk - contributions) 08:02, 27 October 2010 (UTC)[reply]

It's definitely pink. The mineral form, rhodochrosite, is pink/red in color. To me, brown sounds like an Mn(III) or Mn(IV) impurity, possibly caused by the presence of oxygen during preparation of the compound or in storage (or maybe some basic manganese(II) carbonates are brown).--Pyrochem (talk) 06:28, 12 May 2011 (UTC)[reply]

I've just been making some, so took a photo of the filter cake and swapped the picture over. It is very faint pink. I've also edited the box to say the same. Perhaps the original image got mixed up with some other manganese compound. When I was first preparing the carbonate, I tried drying it in a normal atmosphere at 50C for an hour. The colour appeared to be darkening to an orange and half an hour later (one hour thirty in total) I found brown tinges around the edges of the dish. I was preparing the acetate from the carbonate and found this sample refused to react with acetic acid. It seems possible that decomposition of the carbonate to the oxides actually begins at much lower temperatures. This was also noted by someone else. Creating another possible explanation for the original photo showing a clearly brown solid, that it had been dried at high temperatures and decomposed. Anyone passing by with journal access could have a look into the 200C decomposition mention in the article. — Preceding unsigned comment added by Wikichemistry (talk • contribs) 22:39, 7 December 2011 (UTC)[reply]

Refractive index

I cannot verify the value of refractive index written on the page. Can someone tell me where did they get this value from? — Preceding unsigned comment added by 128.84.169.193 (talk) 17:49, 16 May 2012 (UTC)[reply]