Single-crystal Unit-cell Parameters Research Articles

Crystal Structure L-Asparagine Potassium Nitrate Single Crystals

The elemental analysis of the compound confirms the ratio of the compound. The sharp and well defined Bragg peaks obtained in the powder X-ray diffraction pattern confirm the crystalline nature of the compound. The single crystal unit cell parameters of the compound show that the grown crystal belongs to orthorhombic system with space group P. The optical property of the compound was ascertained through UV-visible spectral analysis. The various characteristics absorption bands in the compound were assigned through Fourier transform infra-red (FTIR) spectroscopy. Thenonlinear optical property study indicates that the compound has SHG efficiency 0.50 times greater than that of standard potassium dihydrogen phosphate (KDP).

Piccoliite, NaCaMn3+2(AsO4)2O(OH), a new arsenate from the manganese deposits of Montaldo di Mondovì and Valletta, Piedmont, Italy

AbstractPiccoliite, ideally NaCaMn3+2(AsO4)2O(OH), is a new mineral discovered in the Fe–Mn ore hosted in metaquartzites of the Montaldo di Mondovì mine, Corsaglia Valley, Cuneo Province, Piedmont, Italy. It occurs as small and rare black crystals and aggregates hosted by a matrix of quartz, associated with calcite and berzeliite/manganberzeliite. It has been also found in the Valletta mine near Canosio, Maira Valley, Cuneo Province, Piedmont, Italy, where it occurs embedded in quartz associated with grandaite, hematite, tilasite/adelite and rarely thorianite. The mineral is opaque (thin splinters may be very dark red), with brown streak and has a resinous to vitreous lustre. It is brittle with irregular fracture. No cleavage has been observed. The measured Mohs hardness is ~5–5.5. Piccoliite is non fluorescent. The calculated density is 4.08 g⋅cm–3. Chemical spot analyses by electron microprobe analysis using wavelength dispersive spectroscopy resulted in the empirical formula (based on 10 anions per formula unit) (Na0.64Ca0.35)Σ0.99(Ca0.75Na0.24)Σ0.99(Mn3+1.08Fe3+0.59Mg0.20Ca0.10)Σ1.97(As2.03V0.03Si0.01)Σ2.07O9(OH) and (Na0.53Ca0.47)Σ1.00(Ca0.76Na0.23Sr0.01)Σ1.00(Mn3+0.63Fe3+0.49Mg0.48Mn4+0.34Ca0.06)Σ2.00(As1.97P0.01Si0.01)Σ1.99O9(OH) for the Montaldo di Mondovì and Valletta samples, respectively. The mineral is orthorhombic, Pbcm, with single-crystal unit-cell parameters a = 8.8761(9), b = 7.5190(8), c = 11.689(1) Å and V = 780.1(1) Å3 (Montaldo di Mondovì sample) and a = 8.8889(2), b = 7.5269(1), c = 11.6795(2) Å, V = 781.43(2) Å3 (Valletta sample) with Z = 4. The seven strongest powder X-ray diffraction lines for the sample from Montaldo di Mondovì are [d Å (Irel; hkl)]: 4.85 (57; 102), 3.470 (59; 120, 113), 3.167 (100; 022), 2.742 (30; 310, 213), 2.683 (53; 311, 023), 2.580 (50; 222, 114) and 2.325 (19; 320, 214, 223). The crystal structure (R1 = 0.0250 for 1554 unique reflections for the Montaldo di Mondovì sample and 0.0260 for 3242 unique reflections for the Valletta sample) has MnO5(OH) octahedra forming edge-shared dimers; these dimers are connected through corner-sharing, forming two-up-two-down [[6]M2([4]TO4)4φ2] chains [M = Mn; T = As; φ = O(OH)] running along [001]. These chains are bonded in the a and b directions by sharing corners with AsO4 tetrahedra, giving rise to a framework of tetrahedra and octahedra hosting seven-coordinated Ca2+ and Na+ cations. The crystal structure of piccoliite is closely related to that of pilawite-(Y) as well as to carminite-group minerals that also show the same type of chains but with different linkage. The mineral is named after the mineral collectors Gian Paolo Piccoli and Gian Carlo Piccoli (father and son) (1926–1996 and b. 1953, respectively), the latter having discovered the type material at the Montaldo di Mondovì mine.

Graulichite-(La), LaFe<sup>3+</sup><sub>3</sub>(AsO<sub>4</sub>)<sub>2</sub>(OH)<sub>6</sub>, a new addition to the alunite supergroup from the Patte d'Oie mine, Bou Skour mining district, Morocco

Abstract. The new mineral species graulichite-(La), ideally LaFe33+(AsO4)2(OH)6, has been discovered in the Patte d'Oie mine, Bou Skour mining district, Morocco. It occurs as yellow rhombohedral crystals, up to 0.1 mm in size, with a resinous luster, associated with malachite, agardite-(La), conichalcite, and a still undetermined REE carbonate. Crystals are chemically zoned and two homogeneous domains were identified, corresponding to the empirical chemical formulae (calculated on the basis of 6 cations per formula unit, assuming the occurrence of 14 O atoms) (La0.34Ce0.20Ca0.11Sr0.07Pb0.05K0.04)Σ0.81(Fe2.163+Al0.84Cu0.20)Σ3.20(As1.23P0.39S0.37)Σ1.99O14H6.13 (domain #1) and (La0.38Ce0.22Sr0.10Ca0.09Pb0.05K0.06)Σ0.90(Fe2.603+Al0.49Cu0.20)Σ3.29(As0.91P0.50S0.40)Σ1.81O14H6.53 (domain #2). Single-crystal unit-cell parameters are a=7.252(13), c=16.77(3) Å, V=764(3) Å3, space group R-3m. The eight strongest reflections in the observed X-ray powder diffraction pattern are (d in Å, visually estimated intensity): 5.86, medium; 3.045, strong; 2.511, medium-weak; 2.239, medium; 1.960, medium-weak; 1.813, medium-weak; 1.689, medium-weak; 1.478, medium. Graulichite-(La) belongs to the dussertite group within the alunite supergroup. It is the La analogue of graulichite-(Ce) and the Fe3+ analogue of arsenoflorencite-(La).

The new mineral zolotarevite, Na5Zr[Si6O15(ОН)3]⋅2–3H2O, the first highly hydrated lovozerite-group member from the Lovozero alkaline massif, Kola Peninsula, Russia

AbstractZolotarevite (IMA2020-076), ideally Na5Zr[Si6O15(ОН)3]⋅2–3H2O, is а new mineral of the lovozerite group. The mineral was found in a leucocratic nepheline syenite from Kedykverpakhk Mt., Lovozero alkaline massif, Kola Peninsula, Russia. It occurs as anhedral grains up to 1 mm across and is associated with microcline–perthite, nepheline, sodalite, aegirine, lamprophyllite, lueshite, umbozerite, lomonosovite, nastrophite, a mineral of the kazakovite–tisinalite series, sphalerite and löllingite. Zolotarevite is cherry red, with a vitreous lustre and white streak. The mineral is brittle, with a Mohs hardness of 5. Cleavage was not observed; the fracture is uneven. The measured density is 2.75(5) g⋅cm–3, the density calculated using the empirical formula and single-crystal unit-cell parameters is 2.85 g⋅cm–3. Zolotarevite is anomalously biaxial (–), α = 1.580(2), β = 1.600(2) and γ = 1.602(2) (for λ = 589 nm); 2Vmeas < 10°. Chemical data (electron microprobe, wt.%) are: Na2O 20.41, СаО 0.42, MnO 3.49, Fе2O3 0.55, SiO2 52.46, ТiO2 1.34, ZrO2 11.33, H2O (calculated from the structural formula) 10.20, total 100.20. The empirical formula based оn 6 Si atoms per formula unit is Na4.53Zr0.63Mn0.34Ti0.11Ca0.05Fe3+0.05Si6O14.43(ОН)3.56(H2О)2.11. Zolotarevite is trigonal, space group R${\bar 3}$m, with a = 10.294(6) Å, c = 13.115(8) Å, V = 1203.7(16) Å3 and Z = 3. The crystal structure was solved from single-crystal data and refined to R1 = 0.049. The strongest lines of the powder X-ray diffraction pattern [d in Å (I) (hkl)] are: 7.37 (69) (101); 5.26 (56) (012); 3.686 (64) (202); 3.330 (79) (113); 3.265 (99) (211), 2.640 (100) (024) and 2.576 (60) (220). Zolotarevite is unique in that it is a highly hydrated lovozerite-group mineral with the B site occupied by variable amounts of H2O.

Armellinoite-(Ce), Ca4Ce4+(AsO4)4⋅H2O, a new mineral species isostructural with pottsite, (Pb3Bi)Bi(VO4)4⋅H2O

AbstractArmellinoite-(Ce), ideally Ca4Ce4+(AsO4)4⋅H2O, is a new mineral discovered in Fe–Mn ore in metaquartzites of the Montaldo mine, Corsaglia Valley, Cuneo Province, Piedmont, Italy. It occurs as very small and rare, pale yellow to brown–yellow pseudo-octahedral translucent crystals hosted by a matrix of quartz, hematite, cryptomelane/hollandite, tilasite, muscovite, braunite and montmorillonite. The mineral is translucent, with white streak and has a resinous to vitreous lustre. It is brittle with irregular fracture and fair cleavage parallel to {110} and {100}. Estimated Mohs hardness is ~3–3.5. Calculated density is 4.29 g⋅cm–3. Armellinote-(Ce) is uniaxial (–), ω = 1.795(5), ɛ = 1.765(5) (white light), non-pleochroic and non-fluorescent. Chemical point analyses by WDS-EPMA yielded the empirical formula (based on 17 O+F anions): A(Ca3.89Th0.08Sr0.02La0.03)Σ4.02B(Ce4+0.76Nd0.13Y0.08Gd0.03Sm0.02Pr0.01Dy0.01Ho0.01)Σ1.05[(As4.00P0.01)Σ4.01O4]4⋅(H2O0.85F0.15)Σ2.00. The presence of H2O was confirmed by Raman spectroscopy. The mineral is tetragonal, I41/a, with single-crystal unit-cell parameters a = 10.749(2), c = 12.030(2) Å and V = 1390.0(6) Å3, with Z = 4. The eight strongest X-ray powder diffraction lines are [d Å (Irel; hkl)]: 7.983 (36; 101), 4.443 (23; 2̄11), 2.957 (100; 3̄12), 2.398 (14; 420), 1.875 (22; 424, 325), 1.728 (19; 3̄16), 1.612 (13; 613) and 1.475 (26; 712, 552). The crystal structure (R1 = 0.0284 for 1275 unique reflections) has isolated TO4 (T = As5+) tetrahedra that link Ca2+- or Ce4+-centred polyhedra via common oxygen ligands to form 2D blocks or double-layered (DL) structural units parallel to (001). Armellinoite-(Ce) is isostructural with pottsite, ideally (Pb3Bi)Bi(VO4)4⋅H2O, and closely related to a larger number of anhydrous synthetic compounds. The mineral is named after the mineral collector Gianluca Armellino (b. 1962), who collected the discovery sample.

The Crystal Chemistry of Rathite Based on New Electron-Microprobe Data and Single-Crystal Structure Refinements: The Role of Thallium

Crystal-structure refinements in space group P21/c were performed on five grains of rathite with different types and degrees of thallium, silver, and antimony substitutions, as well as quantitative electron-microprobe analyses of more than 800 different rathite samples. The results of these studies both enlarged and clarified the complex spectrum of cation substitutions and the crystal chemistry of rathite. The [Tl+ + As3+] ↔ 2Pb2+ scheme of substitution acts at the structural sites Pb1, Pb2, and Me6, the [Ag+ + As3+] ↔ 2Pb2+ substitution at Me5, and the Sb-for-As substitution at the Me3 site only. The homogeneity range of rathite was determined to be unusually large, ranging from very Tl-poor compositions (0.16 wt%; refined single-crystal unit-cell parameters: a = 8.471(2), b = 7.926(2), c = 25.186(5) Å, β = 100.58(3)°, V = 1662.4(6) Å3) to very Tl-rich compositions (11.78 wt%; a = 8.521(2), b = 8.005(2), c = 25.031(5) Å, β = 100.56(3)°, V = 1678.4(6) Å3). The Ag content is only slightly variable (3.1 wt%–4.1 wt%) with a mean value of 3.6 wt%. The Sb content is strongly variable (0.20 wt%–7.71 wt%) and not correlated with the Tl content. With increasing Tl content (0.16 wt%–11.78 wt%), a clear increase of the unit-cell parameters a, b, and V, and a slight decrease of c is observed, although this is somewhat masked by the randomly variable Sb content. The revised general formula of rathite may be written as AgxTlyPb16−2(x+y)As16+x+y−zSbzS40 (with 1.6 < x < 2, 0 < y < 3, 0 < z < 3.5). Based on Pb–S bond lengths, polyhedral characteristics and Pb-site bond-valence sums, we conclude that the Pb1 site is more affected by Tl substitution than the Pb2 site. When Tl substitution reaches values above 13 wt% (or 3 apfu), a new phase (“SR”), belonging to the rahite group, appears as lamellar exsolution intergrowths with Tl-rich rathite (11.78 wt%). Rathite is found only in the Lengenbach and Reckibach deposits, Binntal, Canton Wallis, Switzerland.

Wilancookite, (Ba, K, Na)8 (Ba, Li, [])6 Be24 P24 O96·32H2O, a new beryllophosphate with a zeolite framework

Wilancookite, ideally (Ba,K,Na) 8 (Ba,Li,□) 6 Be 24 P 24 O 96 ·32H 2 O, is a new mineral species from the Lavra Ponte do Piaui complex granitic pegmatite, Minas Gerais, Brazil. It occurs as tiny dodecahedral {1 1 0} crystals, deposited on moraesite fibres. Associated primary minerals are albite, montebrasite, Li-bearing micas, cassiterite, elbaite and quartz, while the secondary phosphate association contains fluorapatite, childrenite, eosphorite, zanazziite, greifenstenite, guimaraesite, ushkovite, saleeite and moraesite. The mineral is transparent and colourless, with a vitreous lustre; it is non-fluorescent, brittle, and its streak is white. The estimated Mohs hardness is 4–5, and the calculated density is 3.05 g/cm 3 . Wilancookite is isotropic, colourless, non-pleochroic, with n = 1.560(2) (measured under λ = 590 nm). Electron- and ion-microprobe analyses give (in wt%): P 2 O 5 36.19, SiO 2 0.04, Al 2 O 3 0.41, BaO 34.65, Na 2 O 0.09, K 2 O 0.32, BeO 12.86, Li 2 O 0.50, and H 2 O calc 12.31, total 97.37 wt%. The resulting empirical formula, calculated on the basis of 96 anhydrous oxygen atoms, is (Ba 7.54 K 0.32 Na 0.14 ) Σ8.00 (Ba 3.04 Li 1.57 □ 1.39 ) Σ6.00 Be 24.08 (P 23.88 Al 0.38 Si 0.03 ) Σ24.29 O 96 ·32H 2 O. The single-crystal unit-cell parameters are a = 13.5398(2) A and V = 2482.21(7) A 3 , space group I 23. The eight strongest lines in the powder X-ray diffraction pattern [ d (in A)( I )( hkl )] are: 6.90(60)(2 0 0), 5.54(80)(2 1 1), 3.630(60)(3 2 1, 3 1 2), 3.212(70) (3 3 0, 4 11), 3.043(100)(4 2 0, 4 0 2), 2.885(70)(3 3 2), 2.774(80)(4 2 2), and 2.398(60)(4 4 0). The crystal structure of wilancookite has been refined, based on single-crystal X-ray diffraction data, to R 1 = 4.58%; the beryllophosphate framework is similar to that occurring in pahasapaite, and is based on zeolite-RHO cages. The mineral species and name were approved by the Commission on New Minerals, Nomenclature and Classification of the International Mineralogical Association (IMA2015-034).

Batagayite, CaZn2(Zn,Cu)6(PO4)4(PO3OH)3·12H2O, a new phosphate mineral from Këster tin deposit (Yakutia, Russia): occurrence and crystal structure

Batagayite, CaZn2(Zn,Cu)6(PO4)4(PO3OH)3·12H2O, is a new secondary phosphate mineral from the Kester deposit, Arga-Ynnykh-Khai massif, NE Yakutia, Russia. It is monoclinic, P21, a = 8.4264(4), b = 12.8309(6), c = 14.6928(9) A, β = 98.514(6)o, V = 1571.05(15) A3 and Z = 2 (from single-crystal X-ray diffraction data). Batagayite crystals are blades up to 2 mm long, flattened on {001} and elongated on [100]; blades often grow in radial aggregates. Associated minerals are arsenolite, native copper, epifanovite, fluorapatite, libethenite, Na-analogue of batagayite, pseudomalachite, quartz, sampleite, tobermorite, and Mg-analogue of hopeite. The streak is white and the luster is vitreous. The mineral is brittle and has a perfect cleavage on {001}, no parting was observed. The Mohs hardness is 3. Density, determined by the float-sink method in Clerici solution, is 2.90(3) g/cm3, and the calculated density is 3.02 g/cm3 (using the empirical formula and single-crystal unit-cell parameters). Batagayite is biaxial, optically negative, α = 1.566 ± 0.002, β = 1.572 ± 0.002, γ = 1.573 ± 0.002 at 589 nm. 2V meas. = 40(5)°, 2V calc = 44.3°. Optical orientation: Z is perpendicular to (001), further details unclear. No dispersion or pleochroism were observed. The mean chemical composition determined by electron microprobe is: Na2O 0.31, MgO 1.39, Al2O3 0.55, SiO2 0.48, P2O5 34.37, K2O 0.17, CaO 2.76, MnO 1.03, CuO 5.80, ZnO 35.62, CdO 0.24 wt%. The H2O content estimated from the crystal-structure refinement is 16.83 wt%, giving a total of 99.55 wt%. The empirical formula calculated on the basis of P + Si = 7 is (Zn6.22Cu1.04Ca0.70Mg0.49Mn0.21Al0.15Na0.14K0.05Cd0.03)Σ9.03(P6.89Si0.11)Σ7.00O24.91(OH)3.09·12.10H2O. The mineral easily dissolves in 10% room-temperature HCl. The eight diagnostic lines in the X-ray powder-diffraction pattern are (I-d[A]-hkl): 100-14.59-001, 25-6.34-012, 11-6.02-111, 37-4.864-003, 13-4.766-112, 20-3.102-1 $$\overline {2} \:\overline {4}$$ , 11-2.678-2 $$\overline {3} \:\overline {3}$$ , 16-2.411-044. The crystal structure of batagayite was solved by direct methods and refined to R 1 = 0.069 for 3847 independent reflections with F o > 4σ(F o). It is based upon complex heteropolyhedral [M 8(PO4)4(PO3OH)3(H2O)9]2− layers parallel to the (001) plane. The layer can be considered as consisting of three sublayers, one A and two B. The central A layer has the composition [M 4(PO4)4(H2O)4]4− and consists of the zigzag chains of edge-sharing (MO6) octahedra running parallel to the a axis and linked into layers by sharing peripheral O atoms. The (PO4) tetrahedra are attached above and below the holes created by the linkage of zigzag octahedral chains. The B sublayer consists of chains of (ZnO4) and (PO3OH) tetrahedra. The interlayer space is occupied by the Ca2+ cations and H2O molecules. Batagayite is a secondary low-temperature mineral formed as a result of alteration of primary minerals such as native copper and fluorapatite. On the basis of its structural complexity calculated as 1058.257 bits/cell (taking into account contributions from H atoms), batagayite should be considered as a very complex mineral. The high complexity of batagayite is due to its high hydration state and the modular character of its structure, which contains both octahedral-tetrahedral layers and tetrahedral chains.

Algorithm and program for precise determination of unit-cell parameters of single crystal taking into account the sample eccentricity

A technique has been developed to refine the unit-cell parameters of single crystals with minimization of the influence of instrumental errors on the result. The corresponding computational procedure HuberUB is added to the software package of Huber-5042 diffractometer with a point detector and closedcycle helium cryostat Displex DE-202. The parameters of unit cell, its orientation, the goniometer zero angles, the sample eccentricity, the distances in the goniometer, and the radiation wavelength were refined by the nonlinear least-squares method, which allows imposition of constraints on the unit-cell parameters, depending on the crystal symmetry. The technique is approved on a LuB12 single crystal. The unit-cell parameters are determined in a temperature range of 20–295 K, with an absolute error not larger than 0.0004 A (the relative error is of ~5 × 10–5). The estimates of the unit-cell parameters obtained by the proposed method are evidenced to be unbiased. Some specific features of the behavior of parameters in the ranges of 120–140 and 20–50 K are revealed, which correlate with the anomalies of the physical properties of the crystal.

Albertiniite, Fe2+(SO3)·3H2O, a new sulfite mineral species from the Monte Falò Pb-Zn mine, Coiromonte, Armeno Municipality, Verbano Cusio Ossola Province, Piedmont, Italy

AbstractAlbertiniite, Fe2+(SO3)·3H2O, is a new Fe2+ sulfite trihydrate, related chemically to gravegliaite. It occurs at the Monte Falò Pb-Zn mine near Coiromonte, in the Armeno Municipality, Verbano–Cusio–Ossola Province, Italy. It is an intermediate product of oxidation between iron sulfides and sulfates, forming monoclinic, colourless to pale yellow, transparent crystals with a vitreous lustre. The mineral occurs associated with stolzite, pyromorphite, hinsdalite, plumbogummite, gibbsite, scheelite and jarosite on brittle fractures of quartz veins or chlorite-schist. Albertiniite is optically biaxial (+) with 2V(meas) ≈ 40° and 2V(calc) = 66°. The measured refractive indices, using sodium light (589 nm) are: α = 1.612(2)°, β = 1.618(2)° and γ = 1.632(2)°. The optical axis plane is parallel to the perfect {010} cleavage plane. It is non-fluorescent under shortwave (254 nm) or longwave (366 nm) ultraviolet light. The calculated density is 2.469 g cm–3 (from the crystal-structure refinement), or 2.458 g cm–3 (from the chemical analysis and the single-crystal unit-cell parameters). The empirical formula is (average of 16 spots and based on 3 anhydrous oxygen apfu) (Ca0.001Mg0.001Na0.003)∑1.061(S0.971O3)·2.84H2O, with the H2O content calculated by difference to 100 wt.%. Albertiniite is monoclinic, with space group P21/n. Its unit-cell parameters are: a = 6.633(1), b = 8.831(1), c = 8.773(1) Å, β = 96.106(8)° and V = 511.0(1) Å3, with Z = 4. The eight strongest measured lines in the powder X-ray diffraction pattern are [d in Å, (I/I0), (hkl)]: 4.072 (100) (1̄11), 3.539 (93) (1̄12), 5.533 (27) (1̄01), 6.167 (14) (011), 2.830 (14) (211), 4.998 (14) (101), 4.353 (12) (111) and 3.897 (12) (012). The mineral, which has been approved by the CNMNC, number IMA2015-004, is named albertiniite in honour of Claudio Albertini, an Italian mineral collector and expert in the systematic mineralogy of the Alps and pegmatites.

Chukhrovite-(Ca), Ca4.5Al2(SO4)F13·12H2O, a new mineral species from the Val Cavallizza Pb-Zn-(Ag) mine, Cuasso al Monte, Varese province, Italy

Chukhrovite-(Ca), Ca 4.5 Al 2 (SO 4 )F 13 ·12H 2 O, is the Ca-dominant species of the chukhrovite mineral group. It occurs at the Val Cavallizza Pb–Zn–Ag mine, Cuasso al Monte, Varese province, Italy. Chukhrovite-(Ca) is found as low temperature hydrothermal crystallizations covering the surfaces of brittle fractures crosscutting a marcasite and REE-bearing fluorite vein. Associated minerals include marcasite, gypsum, and hydrated Fe oxides. This new calcium aluminofluoride forms sharp octahedra up to 150 μm in diameter. Crystals are translucent to transparent, colourless to white, with a white streak and a vitreous lustre. Chukhrovite-(Ca) is isotropic with n = 1.432(1), and is non-fluorescent either under short-wave (254 nm) or long-wave (366 nm) ultraviolet light. The mineral is brittle with a Mohs hardness of 3.5(5), and without a distinct cleavage or fracture. Its density, calculated from the single-crystal unit-cell parameters and assuming 12 H 2 O molecules per formula unit, is 2.23 g/cm 3 . The empirical formula, based on 3 (Al + S) atoms per formula unit and calculated from an average of five selected point analyses, is: (Ca 4.33 Na 0.11 Fe 0.03 ) ∑4.47 Al 2.10 (S 0.90 O 3.72 ) F 13.10 ·5.98H 2 O, with the water content calculated by difference to 100 %. Chukhrovite-(Ca) is cubic with space group Fd 3; its single-crystal unit-cell parameters are a = 16.749(1) A and V = 4698.6(1) A 3 , for Z = 8. The eight strongest lines in the X-ray powder diffraction pattern are [ d in A ( I / I 0 ) hkl ]: 9.665 (100) 111, 5.921 (31) 022, 5.053 (16) 113, 4.190 (10) 004, 3.226 (15) 333 and 115, 2.556 (10) 533, 2.182 (12) 355 and 137, 1.915 (17) 626. The mineral, which has been approved by the CNMNC under number IMA 2010-081, is named chukhrovite-(Ca), since it corresponds to the Ca-rich equivalent of chukhrovite-(REE) (REE = Ce, Nd, Y), in which REE are replaced by Ca.

Qingheiite-(Fe+), Na2Fe2+MgAl(PO4)3, a new phosphate mineral from the Sebastiao Cristino pegmatite, Minas Gerais, Brazil

Qingheiite-(Fe 2+ ), ideally Na 2 Fe 2+ MgAl(PO 4 ) 3 , is a new mineral species from the Sebastiao Cristino pegmatite, Minas Gerais, Brazil. It occurs as rims around frondelite grains, included in a matrix of quartz and albite. Frondelite is locally replaced by jahnsite, cyrilovite and Fe-Mn oxides. Qingheiite-(Fe 2+ ) is transparent and exhibits a dark green colour, with a resinous lustre and with a pale to bottle green streak. It is non-fluorescent, brittle, and shows a perfect {010} cleavage. The estimated Mohs hardness is 4. The measured density is 3.6(2) g/cm 3 ; the calculated density is 3.54 g/cm 3 . Qingheiite-(Fe 2+ ) is biaxial negative, with α = 1.692(5), β = 1.718(3), and γ = 1.720(5) (with λ = 590 nm). Pleochroism is from pale pinkish brown ( X ) to pale green ( Y ) and pale bluish grey ( Z ). The calculated 2 V angle is 31°, and a strong dispersion r > v has been observed. The β index is parallel to the b crystallographic axis; α and γ lie in the (010) plane. Electron microprobe analyses gave P 2 O 5 46.51, Al 2 O 3 6.94, Fe 2 O 3 10.58, FeO 11.46, MgO 6.32, MnO 11.23, CaO 0.24, Na 2 O 6.27, K 2 O 0.01, total 99.56 wt. %. The resulting empirical formula, calculated on the basis of 3 P, is (□ 0.65 Na 0.35 ) ∑1.00 (Na 0.58 Mn 2+ 0.40 Ca 0.02 ) ∑1.00 (Fe 2+ 0.68 Mn 2+ 0.32 ) ∑1.00 (Mg 0.72 Fe 3+ 0.23 Fe 2+ 0.05 ) ∑1.00 (Al 0.62 Fe 3+ 0.38 ) ∑1.00 [PO 4 ] 3 . The single-crystal unit-cell parameters are a = 11.910(2), b = 12.383(3), c = 6.372(1) A, β = 114.43(3)°, and V = 855.6(3) A 3 , space group P 2 1 / n . The eight strongest lines in the powder X-ray diffraction pattern [ d (in A)( I )( hkl )] are: 3.468(35)(310), 3.047(100)112, 2.849(80)312, 2.810(35)222, 2.711(40)(330), 2.688(90)(240), 2.500(40) 132; 112, 2.074(30) 313. Qingheiite-(Fe 2+ ) is the Fe 2+ analogue of qingheiite, and belongs to the wyllieite group of minerals. The crystal structure has been refined, based on single-crystal X-ray diffraction data, to R 1 = 2.91%. The mineral species and name were approved by the Commission on New Minerals, Nomenclature and Classification of the International Mineralogical Association (CNMNC-IMA) under number 2009-076.

Nielsbohrite, a new potassium uranyl arsenate from the uranium deposit of Menzenschwand, southern Black Forest, Germany

Nielsbohrite, ideally K(UO 2 ) 3 (AsO 4 )(OH) 4 ·H 2 O, is a new mineral species belonging to the secondary mineral assemblage of the uranium deposit of Menzenschwand in the southern Black Forest, Baden-Wurttemberg, Germany. It is associated with hematite, pyrite, schoepite, metazeunerite and the gangue minerals quartz and barite. Nielsbohrite occurs mainly in euhedral rhombohedron-like crystals reaching 0.15 mm in size, often altered, and showing the forms {001}, {100} or {010}, and {210} or {120}. The mineral is yellow with a vitreous to dull lustre and with a yellowish streak. It is non-fluorescent in ultraviolet light, brittle, and shows an irregular fracture without any visible cleavage. The estimated Mohs hardness is about two, and the calculated density is 5.45–5.65 g/cm 3 . Nielsbohrite is biaxial negative, with n α = 1.756(2), n β = 1.764(2), and n γ = 1.765(2). No pleochroism was observed. The measured 2V angle is 35(5)°, and the calculated 2V angle is 39°, orientation Y = c . A strong r > v dispersion has been observed, with anomalous blue-green and reddish brown interference colours. Electron-microprobe analysis gives K 2 O 1.90, UO 3 83.34, As 2 O 5 10.64, H 2 O* 5.07, total 100.95 wt% (*: calculated value). The resulting empirical formula, calculated on the basis of 10 O + 4 OH structural anions, is (K 0.430□0.570 )(AsO 4 ) 0.987 (UO 2 ) 3.106 (OH) 4 ·1.00H 2 O. The single-crystal unit-cell parameters are a = 8.193(3), b = 11.430(4), c = 13.500(5) A, and V = 1264.1(8) A 3 , with Z = 4, space group Cccm . The strongest lines of the powder X-ray diffraction pattern [ d (in A)( I )( hkl )] are: 6.71(80)(110), 6.03(100)(111), 3.78(70)(113), 3.33(80)(220), 2.96(60)(024), 2.63(50)(204), 1.942(50)(244). The original crystal structure of nielsbohrite is related to those of minerals of the phosphuranylite group, and was refined to a R 1 factor of 11.04 %. The mineral species and its name were approved by the Commission on New Minerals, Nomenclature and Classifications of the International Mineralogical Association (# IMA 2002-045b).

Footemineite, the Mn-analog of atencioite, from the Foote mine, Kings Mountain, Cleveland County, North Carolina, U.S.A., and its relationship with other roscherite-group minerals

Footemineite, ideally Ca2Mn2+□Mn22+Mn22+Be4(PO4)6(OH)4·6H2O, triclinic, is a new member of the roscherite group. It occurs on thin fractures crossing quartz-microcline-spodumene pegmatite at the Foote mine, Kings Mountain, Cleveland County, North Carolina, U.S.A. Associated minerals are albite, analcime, eosphorite, siderite/rhodochrosite, fairfieldite, fluorapatite, quartz, milarite, and pyrite. Footemineite forms prismatic to bladed generally rough to barrel-shaped crystals up to about 1.5 mm long and 1 mm in diameter. Its color is yellow, the streak is white, and the luster is vitreous to slightly pearly. Footemineite is transparent and non-fluorescent. Twinning is simple, by reflection, with twin boundaries across the length of the crystals. Cleavage is good on {01̅1} and {100}. Density (calc.) is 2.873 g/cm3. Footemineite is biaxial (-), nα = 1.620(2), nβ = 1.627(2), nγ = 1.634(2) (white light). 2Vobs = 80°, 2Vcalc = 89.6°. Orientation: X ^ b ~ 12°, Y ^ c ~ 15°, Z ^ a ~ 15°. Elongation direction is c, dispersion: r > v or r < v, weak. Pleochroism: β (brownish yellow) > α = γ (yellow). Mössbauer and IR spectra are given. The chemical composition is (EDS mode electron microprobe, Li and Be by ICP-OES, Fe3+:Fe2+ by Mössbauer, H2O by TG data, wt%): Li2O 0.23, BeO 9.54, CaO 9.43, SrO 0.23, BaO 0.24, MgO 0.18, MnO 26.16, FeO 2.77, Fe2O3 0.62, Al2O3 0.14, P2O5 36.58, SiO2 0.42, H2O 13.1, total 99.64. The empirical formula is (Ca1.89Sr0.03Ba0.02)Σ1.94(Mn2+0.90□0.10)Σ1.00(□0.78Li0.17Mg0.05)Σ1.00(Mn2+3.25Fe2+0.43Fe3+0.09 Al0.03)Σ3.80Be4.30(P5.81Si0.08O24)[(OH)3.64(H2O)0.36]Σ4.00·6.00H2O. The strongest reflection peaks of the powder diffraction pattern [d, Å (I, %) (hkl)] are 9.575 (53) (010), 5.998 (100) (01̅1), 4.848 (26) (021), 3.192 (44) (210), 3.003 (14) (02̅2), 2.803 (38) (1̅03), 2.650 (29) (2̅02), 2.424 (14) (231). Single-crystal unit-cell parameters are a = 6.788(2), b = 9.972(3), c = 10.014(2) Å, α = 73.84(2), β = 85.34(2), γ = 87.44(2)°; V = 648.74 Å3, Z = 1. The space group is P1̅. Crystal structure was refined to R = 0.0347 with 1273 independent reflections (F > 2σ). Footemineite is dimorphous with roscherite, and isostructural with atencioite. It is identical with the mineral from Foote mine described as “triclinic roscherite.” The name is for the Foote mine, type locality for this and several other minerals.

Fluorophlogopite from Biancavilla (Mt. Etna, Sicily, Italy): Crystal structure and crystal chemistry of a new F-dominant analog of phlogopite

Fluorophlogopite, a new F-dominant mineral of the mica group, was found at Monte Calvario, Biancavilla, lower southwestern flanks of Mt. Etna volcano (Catania, Sicily, Italy). The mineral occurs in autoclasts of gray-red altered benmoreitic lavas, primarily associated with fluoro-edenite, alkali-feldspars, clino- and ortho-pyroxenes, fluorapatite, hematite, and pseudobrookite. It was formed by metasomatism of the original lava rocks from very hot fluid enriched in F, Cl, and other incompatible elements. Fluorophlogopite occurs as very thin laminae with a diameter of 200 to 400 μm. Main physical properties are pale yellow in color; yellowish-white in thin section; vitreous to resinous luster; transparent; non-fluorescent; Mohs’ hardness 2-3; brittle and malleable; perfect cleavage on {001}; biaxial (-), αcalc = 1.5430(8), β = 1.5682(5), γ = 1.5688(5) (λ = 589 nm); 2Vmeas = 17(2)°; α = acute bisectrix ⊥ (001); nonpleochroic; Dcalc = 2.830 g/cm3 (using empirical formula and single-crystal unit-cell parameters), Dcalc = 2.842 g/cm3 (using empirical formula and powder cell constants). Infrared spectrum did not show a significant absorption band in the OH-stretching region (3800-3600 cm-1) confirming that the F content of the fluorophlogopite from Biancavilla is close to the stoichiometric value.

Polymorphism of Alprazolam (Xanax®): A Review of its Crystalline Phases and Identification, Crystallographic Characterization, and Crystal Structure of a New Polymorph (Form III)

A new polymorphic form of Alprazolam (Xanax), 8-chloro-1-methyl-6-phenyl-4H-[1,2,4]triazolo-[4,3-alpha][1,4]benzodiazepine, C(17)H(13)ClN(4), has been investigated by means of X-ray powder diffraction (XRPD), single crystal X-ray diffraction, and differential scanning calorimetry (DSC). This polymorphic form (form III) was obtained during DSC experiments after the exothermic recrystallization of the melt of form I. The crystal unit cell dimensions for form III were determined from diffractometer methods. The monoclinic unit cell found for this polymorph using XRPD after indexing the powder diffractogram was confirmed by the cell parameters obtained from single crystal X-ray diffractometry on a crystal isolated from the DSC pans. The single crystal unit cell parameters are: a = 28.929(9), b = 13.844(8), c = 7.361(3) angstroms, beta = 92.82(3) degrees , V = 2944(2) angstroms(3), Z = 8, space group P2(1) (No.4), Dx = 1.393 Mg/m(3). The structure obtained from single crystal X-ray diffraction was used as initial model for Rietveld refinement on the powder diffraction data of form III. The temperature phase transformations of alprazolam were also studied using high temperature XRPD. A review of the different phases available in the Powder Diffraction File (PDF) database for this drug is described bringing some clarification and corrections.

Ferrorosemaryite, NaFe2+Fe3+Al(PO4)3, a new phosphate mineral from the Rubindi pegmatite, Rwanda

Ferrorosemaryite, ideally □ NaFe2+Fe3+Al(PO4)3, is a new mineral species from the Rubindi pegmatite, Rwanda. It occurs as large idiomorphic grains reaching 3 mm, embedded in scorzalite. Associated phosphate minerals are scorzalite, trolleite, montebrasite, bertossaite, brazilianite, with accessory augelite, triplite and lacroixite. The mineral is transparent and exhibits a dark-green to bronze colour, with a resinous lustre and with a greenish to brownish streak. It is non-fluorescent, brittle, and shows a perfect {010} cleavage and a good {101} cleavage. The estimated Mohs hardness is 4. The calculated density is 3.62 g/cm3. Ferrorosemaryite is biaxial negative, with α = 1.730(5), β = 1.758(7), and γ= 1.775(5) (Λ = 590 nm). Pleochroism is from dark green ( X ) to dark brown ( Z ). The measured 2 V angle is 82(1)°, and the calculated 2 V angle is 75°. A strong dispersion r < v has been observed, but the optical orientation has not been determined. Electron microprobe analyses gave P2O5 46.00, Al2O3 9.12, Fe2O3 21.01, FeO 11.10, MgO 0.19, MnO 7.96, CaO 0.44, Na2O 2.85, K2O 0.01, total 98.68 wt. %. The resulting empirical formula, calculated on the basis of 12 O, is □1.00(Na0.42Mn2+0.28Ca0.04□0.26)Σ1.00(Fe2+0.71Mn2+0.24Fe3+0.05)Σ1.00Fe3+1.00(Al0.82Fe3+0.16Mg0.02)Σ1.00[(P0.99□0.01)O4]3. The single-crystal unit-cell parameters are a = 11.838(1), b = 12.347(1), c = 6.2973(6) A, β = 114.353(6)°, and V = 838.5(1) A3, space group P 21/ n . The eight strongest lines in the powder X-ray diffraction pattern [ d (in A)( I )( hkl )] are: 8.102(30)(110), 6.167(50)(020), 5.382(40)(200), 4.054(45)(220), 3.448(65)(310), 3.011(40)(112), 2.693(75)(400), 2.677(100)(240). Ferrorosemaryite is the Fe2+ analogue of rosemaryite, and belongs to the wyllieite group of minerals. The crystal structure of ferrorosemaryite has been refined, based on single-crystal X-ray diffraction data, to R 1 = 2.43 %. The infrared spectrum is similar to those of alluaudite-type phosphates. The mineral species and name were approved by the Commission on New Minerals and Mineral Names of the International Mineralogical Association (no. 2003–063).

Graulichite-(Ce), a new arsenate mineral from the Stavelot Massif, Belgium

Graulichite-(Ce), ideally CeFe 3+ 3 (AsO 4 ) 2 (OH) 6 , is a new mineral species from Hourt, Stavelot Massif, Belgium. It occurs in the most altered parts of a Devillian quartzite (Lower to Middle Cambrian), in close association with arsenopyrite, scorodite, mimetite, pharmacosiderite, and goethite. Graulichite-(Ce) forms 80 to 150 μ spherical aggregates of rhombohedral crystals, 50 to 80 μ length, which show the forms {1012} and {1011}. The mineral is transparent and exhibits a light-green to brownish colour, with a resinous lustre. It is non-fluorescent and shows an irregular fracture, without any perceptible cleavage. The calculated density is 4.42 g/cm 3 . Graulichite-(Ce) is uniaxial negative, with a mean refractive index close to 1.97(1) (λ = 590 nm), pleochroic from light green to yellowish. Electron microprobe analyses gave As 2 O 5 31.20, P 2 O 5 0.03, SO 3 0.06, SiO 2 0.03, Al 2 O 3 3.09, Fe 2 O 3.30.65 , SrO 0.24, PbO 0.07, BaO 3.95, CaO 0.03, La 2 O 3 2.26, Ce 2 O 3 15.73, Nd 2 O 3 2.08, H 2 O (calc.) 8.37, total 97.79 wt. %. The resulting empirical formula, calculated on the basis of 6 cations, is (Ce 0.67 Ba 0.18 La 0.10 Nd 0.09 Sr 0.02 )E] σ1.06 (Fe 2+ 2.68 Al 0.42 ) Σ3.10 [(As 1.89 S 0.01 □ 0.00 )Σ 2.00 O 8 ][(OH) 5.57 (H 2 O) 0.43 ]Σ 6.00 . The single-crystal unit-cell parameters are a = 7.288(2) and c = 16.812(9) A, space group R3m. The seven strongest lines in the X-ray powder-diffraction pattern [ d (in A)( l )( hkil )] are: 3.052(100)(1123), 3.636(40)(1120), 2.239(35)(1017), 1.817(35)(2240), 2.792(30)(0006), 5.906(25)(1011), 1.968(25)(3033). Graulichite-(Ce) is the iron analogue of arsenoflorencite-(Ce), and belongs to the crandallite mineral group, with the alunite-type structure. The crystal structure of graulichite-(Ce) has been refined, based on single-crystal X-ray diffraction data, to R = 0.048.

Calcium fluoride as an internal pressure standard in high-pressure cyrstallography

Cleavage plates of fluorite, CaF2, provide a simple and sensitive pressure calibration based on variation of the cubic unit-cell volume in high-pressure/high-temperature (PT) single-crystal diffraction experiments, when temperature is measured independently by thermocouple. Over the range 0 T 500°C and P 0.04 Mbar (4 GPa), the temperature-pressure-volume equation of state for CaF2 is approximately , where V/Vo is the fractional change in cubic unit-cell volume from T = 0°C and P = 0 Mbar, T is temperature in °C, and P is pressure in Mbar. Crystal structures of CaF2 determined at several PT conditions are evidence of reversibility of single-crystal unit-cell parameters with heating and compression. Nonreversible changes occurred in observed temperature factors and extinction parameter.

Determination of unit-cell parameters of single crystals from rotation patterns

A method is described for determination of unit-cell parameters of single crystals from zero-layer rotation patterns taken in the Straumanis position and indexed by means of corresponding Weissenberg patterns. Values obtained from reflections at the highest diffraction angles (0 > 75°) are compared with those from a least-squares treatment of all high-angle reflections ( > 60°).