Reagents Derived from the 3rd-to-5th-Period Non-Metals Silicon through Xenon

3 Reagents Derived from the 3rd-to-5th-Period Non-Metals, Silicon through Xenon 

A sample of various other phosphates may include Zn5[P30io]2 17H20 and Ba2Zn[cydo-P309]2 IOH2O. 

Arsenic species. Aqueous Zn is precipitated by arsenite or arsenate ion, forming the corresponding white, gelatinous salts, readily soluble in alkalis and acids, including arsenic acids. 

Reduced chalcogens. Sulfane, H2S, precipitates some of the Zn as ZnS, white, from solutions not too acidic with enough CH3CO2 to consume the H3O, precipitation is complete. Alkaline solutions of precipitate ZnS completely except for a small solubility in excess sulfide, although a large excess of NH3, OH or Cl etc. tends to inhibit the reaction. 

Zinc may be precipitated from mixtures withMn, Co and Ni from an armnonia-cal solution by HS . Digestion of the precipitate with cold, dilute HCl dissolves the MnS and ZnS. Then the solution is boiled to eliminate H2S, and the Zn changed to [Zn(OH)4] by an excess of OH plus some Br2, H2O2, or CIO , which precipitate the Mn as Mn02-aq. The excess oxidant is destroyed and the resulting solution tested for Zn , perhaps by adding H2S to give ZnS. 

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