Kia S. Wallwork

Decrespignyite-(Y), a new copper yttrium rare earth carbonate chloride hydrate from Paratoo, South Australia

Abstract Decrespignyite-(Y) is a new copper yttrium rare earth carbonate chloride hydrate from the Paratoo copper mine, near Yunta, Olary district, South Australia. Decrespignyite-(Y) occurs as blue crusts, coatings and fillings in thin fissures on the slatey country rock. Individual pseudohexagonal platelets are typically 10-50 μm in maximum dimension and are often curved. Associated minerals include caysichite-(Y), donnayite-(Y), malachite and kamphaugite-(Y). Electron microprobe and CHN analyses gave: Y2O3 42.2; La2O3 0.1; Pr2O3 0.1; Nd2O3 1.3; Sm2O3 1.0; Gd2O3 4; Tb2O3 0.4; Dy2O3 3.7; Ho2O3 2.6; Er2O3 2.5; CaO 0.5; CuO 10.9; Cl 3.0; CO2 19.8; H2O 10.8, yielding an empirical formula of (Y3.08Gd0.22Dy0.16Ho0.11Er0.10Nd0.06Sm0.05Tb0.02La0.02Pr0.01Ca0.08)∑3.91Cu1.12(CO3)3.70-Cl0.7(OH)5.79·2.4H2O. The simplified formula is (Y,REE)4Cu(CO3)4Cl(OH)5·2H2O. The mineral is royal blue to turquoise-blue in colour, transparent, with a pearly to vitreous lustre and a pale blue streak. No cleavage was observed but the morphology suggests that cleavage would be on [010]. The Mohs’ hardness is estimated to be 4. The strongest lines in the X-ray powder pattern are {dobs (Iobs)(hkl)} 22.79 (30) (010); 7.463 (30) (001); 7.086 (50) (011); 6.241 (100) (021); 4.216 (30) (1̄12); 3.530 (40) (022); 3.336 (30) (032); 2.143 (30) (222, 4̄01). The powder diffraction pattern was indexed on a monoclinic cell with a = 8.899(6), b = 22.77(2), c = 8.589(6) Å, β = 120.06(5)°, V = 1506.3(7) Å3 and Z = 4. The structure of the new mineral could not be determined but powder diffraction data indicate the space group is P2, Pm or P2/m. The measured density is 3.64(2) g/cm3 and the calculated density is 3.645 g/cm3. Decrespignyite-(Y) is biaxial negative with α = 1.604(4) and γ = 1.638(3) with β very close to γ; pleochroism is medium strong; X very pale bluish, Y and Z bluish (with greenish tint). Decrespignyite-(Y) is a supergene mineral which precipitated from mildly basic carbonated ground waters. The mineral is named after Robert Champion de Crespigny, a prominent figure in the Australian mining industry and chancellor of the University of Adelaide.

A model for the structure of the hydrated aluminum phosphate, kingite determined by ab initio powder diffraction methods

Abstract [The crystal structure of kingite, Al3(PO4)2(F5OH)2·B(H2O, OH), a secondary mineral from a Cambrian-Precambrian phosphate deposit at Tom’s Quarry, near Kapunda, South Australia, has been determined from a powder sample using synchrotron X-ray diffraction data. The structure was determined ab initio by direct methods and refined to Rbragg = 0.022 and Rwp = 0.039 using the Rietveld method. The triclinic structure was solved and refined in the space group P1̅, a = 9.377(1), b = 10.113(1), c = 7.138(1) A, σ = 97.60(1), β= 100.88(1), γ = 96.01(1)°, V= 653.0(1) A3, Z= 2. The structure of kingite contains finite strings of three corner sharing AlΦ6 octahedra (where Φ represents O, OH-, F-, or H2O). These strings are cross-linked via PO4 tetrahedra to produce layers that are perpendicular to [100]. The layers are linked via hydrogen bonding through H2O located in the interlayer space. Kingite is shown to have a different stoichiometry to that reported earlier. The relationship of kingite to the structures of wavellite, Al3(P04)2(OH)3·5H2O, and mitryaevaite, A15(PO4)2[(P,S)O3(OH,O)]2F2(OH)2(H2O)8-6.48H2O, are briefly discussed.

Paratooite-(La), a new lanthanum-dominant rare-earth copper carbonate from Paratoo, South Australia

Abtract Paratooite-(La) is a new lanthanum-dominant rare-earth copper carbonate from the Paratoo copper mine, near Yunta, Olary district, South Australia. Paratooite-(La) occurs as sheaves and radiating sprays of blade-like to tabular pale blue crystals in thin fissures in a slaty country rock. Individual crystals are typically 50-200 μm in maximum dimension but <5 μm thick. Associated minerals include donnayite-(Y), kamphaugite-(Y), and bastnäsite-(La). Electron microprobe and CHN analyses gave: La2O3 26.47; Pr2O3 7.74; Nd2O3 8.15; Sm2O3 0.66; Gd2O3 0.85; Y2O3 0.72; CaO 7.57; SrO 3.15; Na2O 3.3; CuO 5.77; F 0.24; CO2 32.05; NO2 1.12; -O=F -0.10; sum 100.03, yielding an empirical formula of (La3.54Ca2.94Na2.32Nd1.05Pr1.03Sr0.66Y0.14Gd0.10Sm0.0.8)S11.86Cu1.58(C15.84N0.53)O47.76F0.24. The simplified formula is (REE,Ca,Na,Sr)6Cu(CO3)8 or possibly REE3(Ca,Sr)2NaCu(CO3)8. The mineral is pale turquoise-blue to pale blue in colour, transparent, with a pearly to vitreous lustre and a pale blue streak. No cleavage was observed but the morphology and TEM studies indicate a cleavage parallel to {100}. The Mohs hardness is estimated to be 4. The strongest lines in the X-ray powder pattern are [dobs (Iobs) (hkl)]: 5.047 (53) (200); 4.786 (49) (021); 3.957 (43) (220); 3.468 (43) (012, 221); 2.927 (100) (202); 2.530 (52) (241); 2.344 (22) (420,103); 2.232 (20) (421). A synchrotron powder diffraction pattern was indexed on a primitive orthorhombic cell with a = 10.0862(5), b = 12.8088(6), c = 7.2360(4) Å, V = 934.8(1) Å3 and Z = 2. The crystal structure of the new mineral could not be determined but powder diffraction data indicate the space group is probably P222, Pmmm, P2221 or Pmm2. The measured density is 3.68(3) g/cm3 and the calculated density is 3.78 g/cm3. Paratooite-(La) is biaxial negative with α = 1.605(3), β = 1.696(3) and γ = 1.752(2); pleochroism is medium strong; X very pale bluish, Y and Z bluish (with greenish tint) with absorption Z ≈ Y ≫ X. Paratooite-(La) is a supergene mineral which precipitated from mildly basic carbonated groundwaters. The mineral is named for the type locality.

{Δ-1,4,7,10-Tetrakis[(S)-2-hydroxy­propyl-κO]-1,4,7,10-tetra­aza­cyclo­do­dec­ane-κ4N}cad­mium(II) 4-nitrophenolate per­chlor­ate hydrate

Crystallization of [Cd(S-thpc12)](ClO4)2·H2O {S-thpc12 is 1,4,7,10-tetraxadkis[(S)-2-hyxaddroxxadyxadpropyl]-1,4,7,10-tetraxadazaxadcyxadclo-doxaddecxadane} in the presence of sodium p-nitrophenolate forms the title complex, [Cd(C20H44N4O4)](C6H4NO3)(ClO4)·H2O, in which p-nitrophenolate and water separately hydrogen bond to a different pair of cis-related pendant hydroxyl groups which, together with the four N atoms, are themselves bound to CdII in an approximately square antiprismatic arrangement. The diastereoselectivity of the complex-forming process is apparent from the fact that both different disymmetric cations in the asymmetric unit have the same Δ helicity.