cobalt_pigment

Filtering (ME152) Whatman 14 um:

* (ME164) liq; very sly pink clear.

* (ME165) ppt; lilac.

Pipeted out the supernatant liq (clear white) of (ME1xa). Dumped the black ppt (~2mm) into the filtration ((1)), that is, merged with (ME151).

Collected (ME165) from filter paper as a gelatinous dark lilac mass.  Tried to put into a test tube but stuck to walls.   Added 3 mL H2O to wash the walls.  Result was a thick suspension that did not settle.  Added ~5 mL EtOH 99% in attempt to help settle.  Did not work, but suspension became brown-gray.  Heated in BM; still did not settle.  

Filtered (ME11ra) (extract from 'brown' residues with HAc, then precipitated with Na2CO3) through the same paper used for filtering (ME152):

* liq merged into (ME164).

* ppt (ME166) brownish lilac; washed with lots of H2O.

Re-filtering (ME165) (carbonate + H2O + EhOH):

* liq (ME167) clear white discarded.

* ppt (ME168) dark sly greenish brown.

Filtering (ME1ps):

* liq (ME169) clear white.

* ppt (ME170) orangish light brown.

Added 1.5 mL Na2CO3 sol (16 C sat) to (ME164) (clear very light pink). No change.  (Maybe the pink hue is a CO2/cobalt complex?  Maybe solubte cobalt bicarbonate?)

Transferred carbonate ppts to test tubes and added some (H1):

* (ME168) (small amt): added 2 mL, turned dark blue.

* (ME166) (larger amount): added 4 mL, turned witish med blue, and hot.

* (ME170) (a bit larger amount): added 6 mL, turned royal blue, and hot.

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