Neodymium nitrate

Many of the compounds (salts) of neodymium are skin irritants and toxic if inhaled or ingested. Some are explosive (e.g., neodymium nitrate [Nd(NOj)j]). 

The aF3,2- 4F5,2 emission of Nd3+ at 885 nm can also be monitored in a rather similar way, and a study of emission lifetimes together with absorption spectra for the hypersensitive Nd3+ transitions, e.g. %/2- 4Gs/2, has been made in order to investigate the solvation of neodymium nitrate and perchlorate in MeCN, Me2CO, DMSO or DMF. Excited lifetimes varied from 300 ns in Me2CO to 2300 ns in CD3CN. It was found that species Nd(N03) (3 ")+ were formed, where n = 1-5, on addition of NOJ ions to perchlorate solutions, but that addition of DMSO to Nd(CI04)3 in MeCN gave [Nd(DMSO) ]3+, where n = 9.7 0.8.618... 

The functionalized membranes were tested in ion transport experiments to evaluate the effect of type and level of functionalization8. The membranes were contacted on one side with a feed solution containing 1 mM concentrations of sodium, zinc, ferric and/or neodymium nitrate salts. The receiving solution in contact with the other side of the... 

Nd203 (c). Muthmann and Beck1 measured the heat of combustion of neodymium to be 434.8. We have labeled this the "high temperature form, and have estimated the heat of formation of the low temperature form (as prepared from neodymium nitrate, for example) to be 427. 

Belair, S., Labet, A., Mariet, C., Dannus, P. 2005. Modeling of the extraction of nitric acid and neodymium nitrate from aqueous solutions over a wide range of activities by CMPO. Solvent Extr. Ion Exch. 23 (4) 481 199. 

In the DMDBTDMA-alkane system (37, 140), the third phase is a gel when neodymium nitrate or thorium nitrate are extracted at high concentration, but... 

Neodymium carrier 10 mg Nd3+/mL. Dissolve 6.38 g of Nd203 in a beaker with 10 mL of concentrated nitric acid heat if necessary. Transfer solution to flask and dilute to 250 mL with de-ionized water. If neodymium nitrate or neodymium chloride is available, the carrier may be prepared from one of these salts, with the weight of salt recalculated to match the chemical formula. 

The ratio of the size of the metal ion and the radius of the internal cavity of the macrocyclic polyether determines the stoichiometry of these complexes. The stoichiometry of these complexes also depends on the coordinating ability of the anion associated with the lanthanide. For example, 12-crown-4 ether forms a bis complex with lanthanide perchlorate in acetonitrile while a 1 1 complex is formed when lanthanide nitrate is used in the synthesis [66]. Unusual stoichiometries of M L are observed when L = 12 crown-4 ether and M is lanthanide trifluoroacetate [67]. In the case of 18-crown-6 ligand and neodymium nitrate a 4 3 stoichiometry has been observed for M L. The composition of the complex [68] has been found to be two units of [Nd(18-crown-6)(N03)]2+ and [Nd(NCh)<--)]3. A similar situation is encountered [69] when L = 2.2.2 cryptand and one has [Eu(N03)5-H20]2- anions and [Eu(2.2.2)N03]+ cations. It is important to note that traces of moisture can lead to polynuclear macrocyclic complexes containing hydroxy lanthanide ions. Thus it is imperative that the synthesis of macrocyclic complexes be performed under anhydrous conditions. 

In this chapter the thermodynamic analysis of the Nd(N03)3-HN03-H20 system is presented. The determination of the activity and the activity coefficient of the free neodymium (III) ion and the development of an accurate model for the activity behavior of aqueous binary electrolyte solutions consisting of the neodymium nitrate and nitric acid are presented. 

Table II. Activities and Activity Coefficients of the Free Neodymium Ion in Neodymium Nitrate Aqueous Solutions...

The values of the two stability constants (Ki and K2) for the two neodymium-nitrate complexes existing in the Nd(N03)3-HN03 aqueous phase were determined from the total ionic strengths of the aqueous phase using Equations 20 and 21. The total ionic strength was obtained from the relationship ... 

Figure 7. Average water activity as a function of ionic strength fraction of neodymium nitrate in the Nd(N03)3-HN03-H20 binary electrolyte solution...

Table VIII. Nitrate Electrode Measurements on Neodymium Nitrate—Nitiric Acid Solutions at Constant Total Ionic Strength (/)...

Fraction of neodymium nitrate making up the total ionic strength. 5 Hydrogen ion concentration of the aqueous phase. 

Fraction of neodymium nitrate making up the total ionic strength. 

The liquid-liquid extraction feed solutions were prepared by dilution of the neodymium nitrate stock solution with distilled water and nitric acid. These then were contacted with equal volumes of 1M HDEHP in separatory funnels, agitated for. 5 hr by a mechanical shaker, allowed to separate for. 5 hr, shaken another. 5 hr, then allowed to settle for 12 hr before the phases were separated carefully. A volumetric sample of the organic phase was back-extracted four times with an equal volume of 6M HN03. This solution was evaporated to dryness in order to remove the excess acid and then diluted to an appropriate concentration. The pH of this solution was adjusted to 3.0 to eliminate any hydrolysis effects... 

The nitrate ion activities in the aqueous phase were measured with a nitrate ion selective electrode taking into account the presence of high hydrogen ion concentration by calibration of the nitrate electrode with nitric acid. The nitrate ion concentration in the organic phase owing to the extraction of neodymium complexes by HDEHP was determined by back-extraction of the organic phase with 3M sulfuric acid, dilution, and analysis with a nitrate ion electrode calibrated for different nitrate and sulfate concentrations. The amount of the nitrate species extracted into the organic phase increases as the initial neodymium nitrate concentration increases. 

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