Manganese Rare Earth Elements

The only element whose concentration is recommended to be certified is iron. An iron reference material will also clearly be useful for studying other important metals such as zinc, manganese, copper, molybdenum, cobalt, vanadium, lead, aluminum, cadmium, and the rare earth elements. It is thus desirable to assure stability for some of these elements in addition to iron. 

Table 4.4. Concentrations of rare-earth elements and manganese (ppm) in several apatites ...

Doped manganite perovskites exhibiting CMR have the general formula REi fM f]V[n03 where RE represents a rare earth element and M a divalent metal such as Cu, Cr, Ba, or Pb. The divalent RE ions and divalent M ions occupy the A sites in the perovskite structure (Figure 9.14) and have 12-fold coordination to oxygen. The Mn ions occupy the octahedral B sites. (1- of the manganese ions... 

Just as silicon in the first group shows similarities with titanium on the one hand and with germanium on the other, there exists in exactly the same way a relationship between the elements of the 2nd and 3rd groups, for example from zirconium to cerium with an atomic weight of 140 on the one hand and from zirconium to an unknown element with an atomic weight aroimd 181 on the other. There are a large number of rare-earth elements in between these two elements which are related to one another like the central elements of the 3rd series placed between manganese and zinc. (Thomsen, 1895 Trifonov, 1966). 

The most prominent geochemical difference, and one that has been exploited in the classification of manganese deposits (see, e.g., Nicholson (1992)), is the extreme concentration of the heavy metals such as cobalt, nickel, and copper in the hydrogenous deposits. A comparison of the analyses in Table 2 for hydrogenous deposits to those for ancient deposits plus modern hydrothermal deposits shows a 10-fold or higher enrichment in the hydrogenous deposits for cobalt, nickel, and copper, but also for lead, thorium, and total rare earth elements (REEs). The ancient deposits and the modem hydrothermal deposits are similar for most elements the ancient deposits show some enrichment in sulfur, arsenic, and selenium, whereas the modem hydrothermal deposits are relatively enriched in nickel, copper, and molybdenum. 

Fleet A. J., Bostrom K., Laubier L., and Smith K. L. (1983) Hydrothermal and hydrogenous ferro-manganese deposits do they form a continuum The rare earth element evidence. In Hydrothermal Processes at Seafloor Spreading Centers (ed. P. A. Rona). Plenum, New York, pp. 535-555. 

The Arsenazo III method has been utilized for determining Sc in minerals [51]. Scandium in mixtures with rare earth elements was determined by derivative spectrophotometry with the use of Chlorophosphonazo-p-Cl [27]. p-Acetyl-chlorophosphonazo with Ce(III) has been used for determining Sc in copper, aluminium, manganese, and magnesium alloys [28]. Traces of scandium in silicate rocks and sediments were determined with the use of Bromopyrogallol Red [43]. 

If the region between helium and uranium contains 91 elements then five are as yet undiscovered. These have been predicted and named (1) eka-manganese with an atomic number 43 and an atomic weight approximately 100 (2) dwi-manganese, atomic number 75 falling between tungsten and osmium (3) eka-iodine, atomic number 85 (4) eka-neodym-ium, a rare earth element of atomic number 61 and (5) eka-caesium of atomic number 87. Of these, greatest interest has... 

S.I., 1998. Rare earth elements in manganese nodules from the South Atlantic Ocean as indicators of oceanic bottom water flow. Marine Geology, 146 33-52. 

Fig. 62. Partial enthalpy at infinite dilution in liquid manganese of rare earth elements. The references of the data are quoted in table 20.

Carlo, E. H. D., and Pruszkowski, E. (1995). Laser ablation ICP-MS determination of alkaline and rare earth elements in marine ferro-manganese deposits. At. Spectrosc. 16(2), 65. 

This section deals with the ternary compounds formed by rare earth elements and chalcogenides with the elements of groups VI through VIII chromium, manganese, iron, cobalt, nickel and molybdenum. 

---