Applications and Future Prospects for X-ray Fluorescence Microprobe Analysis

2007 ◽  
Vol 13 (S02) ◽  
Author(s):  
B Lai ◽  
S Vogt ◽  
J Maser ◽  
B Ravel ◽  
K Kemner ◽  
...  
Keyword(s):  
Microprobe Analysis ◽  
Future Prospects ◽  
X Ray

Fluorescence effects in quantitative microprobe analysis

1990 ◽  
Vol 48 (2) ◽  
pp. 188-189
Author(s):  
S.J.B. Reed
Keyword(s):  
Microprobe Analysis ◽  
Depth Distribution ◽  
Exciting Radiation ◽  
Primary Radiation ◽  
List Type ◽  
Type Number ◽  
Computing Power ◽  
X Ray ◽  
Fluorescent Radiation

Characteristic fluorescenceThe theory of characteristic fluorescence corrections was first developed by Castaing. The same approach, with an improved expression for the relative primary x-ray intensities of the exciting and excited elements, was used by Reed, who also introduced some simplifications, which may be summarized as follows (with reference to K-K fluorescence, i.e. K radiation of element ‘B’ exciting K radiation of ‘A’):1.The exciting radiation is assumed to be monochromatic, consisting of the Kα line only (neglecting the Kβ line).2.Various parameters are lumped together in a single tabulated function J(A), which is assumed to be independent of B.3.For calculating the absorption of the emerging fluorescent radiation, the depth distribution of the primary radiation B is represented by a simple exponential.These approximations may no longer be justifiable given the much greater computing power now available. For example, the contribution of the Kβ line can easily be calculated separately.

Do selenium hyperaccumulators affect selenium speciation in neighboring plants and soil? An X-Ray Microprobe Analysis

2015 ◽  
Vol 17 (8) ◽  
pp. 753-765 ◽  
Author(s):  
Ali F. El Mehdawi ◽  
Stormy D. Lindblom ◽  
Jennifer J. Cappa ◽  
Sirine C. Fakra ◽  
Elizabeth A. H. Pilon-Smits
Keyword(s):  
Microprobe Analysis ◽  
Selenium Speciation ◽  
X Ray

Coiraite, (Pb,Sn2+)12.5As3Fe2+Sn4+5 S28: a franckeite-type new mineral species from Jujuy Province, NW Argentina

2008 ◽  
Vol 72 (5) ◽  
pp. 1083-1101 ◽  
Author(s):  
W. H. Paar ◽  
Y. Moëlo ◽  
N. N. Mozgova ◽  
N. I. Organova ◽  
C. J. Stanley ◽  
...  
Keyword(s):  
Low Temperature ◽  
Microprobe Analysis ◽  
Electron Microprobe Analysis ◽  
Mineral Species ◽  
New Mineral ◽  
Hydrothermal Solutions ◽  
X Ray ◽  
New Mineral Species ◽  
Primary Mineral ◽  
The Ideal

AbstractCoiraite, ideally (Pb,Sn2+)12.5As3Fe2+Sn4+S28, occurs as an economically important tin ore in the large Ag-Sn-Zn polymetallic Pirquitas deposit, Jujuy Province, NW-Argentina. The new mineral species is the As derivative of franckeite and belongs to the cylindrite group of complex Pb sulphosalts with incommensurate composite-layered structures. It is a primary mineral, frequently found in colloform textures, and formed from hydrothermal solutions at low temperature. Associated minerals are franckeite, cylindrite, pyrite-marcasite, as well as minor amounts of hocartite, Ag-rich rhodostannite. arsenopyrite and galena. Laminae of coiraite consist of extremely thin bent platy crystals up to 50 urn long. Electron microprobe analysis (n = 31) gave an empirical formula Pb11.21As2.99Ag0.13Fe1.10Sn6.13S28.0 close to the ideal formula (Pb11.3Sn2+1.2)Σ=12.5As3Fe2+Sn4+S28. Coiraite has two monoclinic sub-cells, Q (pseudotetragonal) and H (pseudohexagonal). Q: a 5.84(1) Å, b 5.86(1) Å, c 17.32(1) Å, β 94.14(1)°, F 590.05(3) Å3, Z = 4, a:b:c = 0.997:1:2.955; H (orthogonal setting): a 6.28(1) Å, b 3.66(1) Å, c 17.33(1) Å, β 91.46(1)°, V398.01(6) Å3, Z = 2, a∶b∶c = 1.716∶1∶4.735. The strongest Debye-Scherrer camera X-ray powder-diffraction lines [d in Å, (I), (hkl)] are: 5.78, (20), (Q and H 003); 4.34, (40), (Q 004); 3.46, (30), (Q and H 005); 3.339, (20), (Q 104); 2.876, (100), (Q and H 006); 2.068, (60), (Q 220).

Potassic-jeanlouisite from Leucite Hill, Wyoming, USA, ideally K(NaCa)(Mg4Ti)Si8O22O2: the first species of oxo amphibole in the sodium–calcium subgroup

2019 ◽  
Vol 83 (4) ◽  
pp. 587-593
Author(s):  
Roberta Oberti ◽  
Massimo Boiocchi ◽  
Frank C. Hawthorne ◽  
Giancarlo Della Ventura ◽  
Gunnar Färber
Keyword(s):  
Microprobe Analysis ◽  
Electron Microprobe Analysis ◽  
Structure Refinement ◽  
Crystal Structure Refinement ◽  
Unit Cell Parameters ◽  
X Ray ◽  
International Mineralogical Association ◽  
Cell Parameters ◽  
Mineralogical Association ◽  
Sodium Calcium

AbstractPotassic-jeanlouisite, ideally K(NaCa)(Mg4Ti)Si8O22O2, is the first characterised species of oxo amphibole related to the sodium–calcium group, and derives from potassic richterite via the coupled exchange CMg–1W${\rm OH}_{{\rm \ndash 2}}^{\ndash}{} ^{\rm C}{\rm Ti}_1^{{\rm 4 +}} {} ^{\rm W}\!{\rm O}_2^{2\ndash} $. The mineral and the mineral name were approved by the International Mineralogical Association Commission on New Minerals, Nomenclature and Classification, IMA2018-050. Potassic-jeanlouisite was found in a specimen of leucite which is found in the lava layers, collected in the active gravel quarry on Zirkle Mesa, Leucite Hills, Wyoming, USA. It occurs as pale yellow to colourless acicular crystals in small vugs. The empirical formula derived from electron microprobe analysis and single-crystal structure refinement is: A(K0.84Na0.16)Σ1.00B(Ca0.93Na1.02Mg0.04${\rm Mn}_{{\rm 0}{\rm. 01}}^{2 +} $)Σ2.00C(Mg3.85${\rm Fe}_{{\rm 0}{\rm. 16}}^{2 +} $Ni0.01${\rm Fe}_{{\rm 0}{\rm. 33}}^{3 +} {\rm V}_{{\rm 0}{\rm. 01}}^{3 +} $Ti0.65)Σ5.01T(Si7.76Al0.09Ti0.15)Σ8.00O22W[O1.53F0.47]Σ2.00. The holotype crystal is biaxial (–), with α = 1.674(2), β = 1.688(2), γ = 1.698(2), 2Vmeas. = 79(1)° and 2Vcalc. = 79.8°. The unit-cell parameters are a = 9.9372(10), b = 18.010(2), c = 5.2808(5) Å, β = 104.955(2)°, V = 913.1(2) Å3, Z = 2 and space group C2/m. The strongest eight reflections in the powder X-ray pattern [d values (in Å) (I) (hkl)] are: 2.703 (100) (151); 3.380 (87) (131); 2.541 (80) ($\bar 2$02); 3.151 (70) (310); 3.284 (68) (240); 8.472 (59) (110); 2.587 (52) (061); 2.945 (50) (221,$\bar 1$51).

Crystal-chemical aspects of the roméite group, A2Sb2O6Y, of the pyrochlore supergroup

2017 ◽  
Vol 81 (6) ◽  
pp. 1287-1302
Author(s):  
Ferdinando Bosi ◽  
Andrew G. Christy ◽  
Ulf Hålenius
Keyword(s):  
Microprobe Analysis ◽  
Electron Microprobe Analysis ◽  
Structural Parameters ◽  
Chemical Information ◽  
Crystal Chemical ◽  
X Ray Diffraction ◽  
Structural Variations ◽  
X Ray ◽  
End Members ◽  
Charge Balancing

AbstractFour specimens of the roméite-group minerals oxyplumboroméite and fluorcalcioroméite from the Långban Mn-Fe deposit in Central Sweden were structurally and chemically characterized by single-crystal X-ray diffraction, electron microprobe analysis and infrared spectroscopy. The data obtained and those on additional roméite samples from literature show that the main structural variations within the roméite group are related to variations in the content of Pb2+, which is incorporated into the roméite structure via the substitution Pb2+→A2+ where A2+ = Ca, Mn and Sr. Additionally, the cation occupancy at the six-fold coordinated B site, which is associated with the heterovalent substitution BFe3+ + Y☐→BSb5++YO2-, can strongly affect structural parameters.Chemical formulae of the roméite minerals group are discussed. According to crystal-chemical information, the species associated with the name ‘kenoplumboroméite’, hydroxycalcioroméite and fluorcalcioroméite most closely approximate end-member compositions Pb2(SbFe3+)O6☐, Ca2(Sb5+Ti) O6(OH) and (CaNa)Sb2O6F, respectively. However, in accord with pyrochlore nomenclature rules, their names correspond to multiple end-members and are best described by the general formulae: (Pb,#)2(Sb,#)2O6☐, (Ca,#)2(Sb,#)2O6(OH) and (Ca,#)Sb2(O,#)6F, where ‘#’ indicates an unspecified charge-balancing chemical substituent, including vacancies.

Synthesis, structure and thermal expansion of the phosphates M0.5+x M′x Zr2−x (PO4)3 (M, M′–metals in oxidation state +2)

2017 ◽  
Vol 89 (4) ◽  
pp. 523-533 ◽  
Author(s):  
Elena Asabina ◽  
Vladimir Pet’kov ◽  
Pavel Mayorov ◽  
Dmitriy Lavrenov ◽  
Igor Schelokov ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Thermal Treatment ◽  
Ir Spectroscopy ◽  
Microprobe Analysis ◽  
Electron Microprobe Analysis ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
X Ray ◽  
Structural Types ◽  
The Difference

AbstractThe phosphates M0.5+x M′x Zr2−x (PO4)3 (M–Ca, Mn, Co, Sr, Cd, Ba, Pb; M′–Mg, Mn, Co) were synthesized by sol-gel method with the following thermal treatment of reaction mixtures. X-ray diffraction, IR spectroscopy and electron microprobe analysis showed that the obtained phosphates crystallized in Sc2(WO4)3 (SW) and NaZr2(PO4)3 (NZP) structural types. Both types of crystal structures are based on a framework comprised of octahedra and tetrahedra, the difference between them is fragments orientation. Thermal expansion of the phosphates was studied in the temperature range 20–800°C. Some compounds were found to belong to low-expanding materials (αav ~2·10−6°C−1).

ROOM TEMPERATURE MAGNETIC ANOMALIES IN BENZENE TREATED Bi–Pb–Sr–Ca–Cu–O POWDER

1991 ◽  
Vol 05 (21) ◽  
pp. 1447-1456 ◽  
Author(s):  
A. R. HARUTUNYAN ◽  
L. S. GRIGORYAN ◽  
A. S. KUZANYAN ◽  
A. A. KUZNETSOV ◽  
A. A. TERENTIEV ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Chemical Composition ◽  
Room Temperature ◽  
Microprobe Analysis ◽  
Magnetic Anomalies ◽  
X Ray Diffraction ◽  
X Ray ◽  
Two Samples ◽  
Field Dependent ◽  
History Of

Two samples of benzene-treated Bi–Pb–Sr–Ca–Cu–O powder exhibited at 300 K magnetic field dependent diamagnetism and magnetization irreversibility. The treatment with benzene resulted also in the appearance of microwave absorption at low magnetic fields, while is sensitive to magnetic history of the sample. From X-ray diffraction data one can see that upon benzene treatment the reflections of 85 K and 110 K phases do not change practically, but a series of new reflections appeared, indicating a lattice modulation with 4.9 nm periodicity. A microprobe analysis revealed substantial inhomogeneity of chemical composition across the samples. The room temperature anomalies were weakened in one sample and vanished in the second upon thermal cycling.

Sign in / Sign up

Export Citation Format

Share Document