Ferric ammonium citrate mixture

Ferric ammonium citrate [1185-57-5]—A mixture of complex chelates prepared by the iateraction of ferric hydroxide with citric acid ia the presence of ammonia. The chelates occur ia brown and green forms, are dehquescent ia air, and are reducible by light. 

Chemical Designations - Synonyms Ammonium ferric citrate, Ferric ammonium citrate (brown), Ferric ammonium citrate (green) Chemical Formula Mixture of FeC HjOy, (NiyjHCjjHjOy, and water of hydration. 

The presence of permanent [Fe2S2] clusters in holo-NifU impeded spectroscopic characterization of transient clusters assembled in a NifS-mediated process. However, unambiguous evidence for NifS-directed assembly of oxidatively and reductively labile [Fe2S2] " clusters on NifU-1 was obtained using the combination of UV-visible absorption and resonance Raman spectroscopies (Yuvaniyama et al. 2000). The anaerobic reaction mixture involved NifU ferric ammonium citrate P-mercaptoethanol l-cysteine NifS in a 50 100 5000 1000 1 ratio. The presence of catalytic amounts of NifS facilitated meaningful UV-visible absorption results and monitoring the time course of cluster assembly. Although ferric ammonium citrate was used for these cluster assembly studies, control experiments... 

Figure 4. The survival of E. coli on microbiostatic serum-agar medium around wells charged at 10, 15, 24, and 36 hr of incubation at 4°C and 37°C with a solution of ferric ammonium citrate (5 i g iron/well), spent medium, or iron-spent medium mixture (25)...

Ferric Ammonium Citrate — (i) Chemical Designations — Synonyms Ammonium ferric citrate, Ferric ammonium citrate (brown), Ferric ammonium citrate (green) Chemical Formula Mixture of FeCjHj07, (NH4)2HC((Hj07, and water of hydration (ii) Observable Characteristics — Physical State (as shipped) Solid Color Red, green, or brown Odor None (iii)... 

The resulting salt, whilst readily soluble in dilute mineral acids, is insoluble in cold acetic acid, phosphoric acid, and sodium phosphate. It is slightly soluble in citric and tartaric acid solutions, and readily dissolves m neutral aqueous ammonium citrate, yielding a green solution with a brownish tint.3 The salt is insoluble in water, but hot water hydrolyses it, and boiling with excess of ammonia solution converts it into a mixture of ferric hydroxide 4 and ferric phosphate, or if the ammonia is present in great excess the ferric phosphate may be entirely decomposed. Thus —... 

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