English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

Chromschieffelinite, Pb 10 Te 6 O 20 (OH) 14 (CrO 4 )(H 2 O) 5 , is a new tellurate from Otto Mountain near Baker, California, named as the chromate analog of schieffelinite, Pb 10 Te 6 O 20 (OH) 14 (SO 4 )(H 2 O) 5 . The new mineral occurs in a single 1 mm vug in a quartz vein. Associated mineral species include: chalcopyrite, chrysocolla, galena, goethite, hematite, khinite, pyrite, and wulfenite. Chromschieffelinite is orthorhombic, space group C222 1 , a = 9.6646(3), b = 19.4962(8), c = 10.5101(7) Å, V = 1980.33(17) Å 3 , and Z = 2. Crystals are blocky to tabular on {010} with striations parallel to [001]. The forms observed are {010}, {210}, {120}, {150}, {180}, {212}, and {101}, and crystals reach 0.2 mm in maximum dimension. The color and streak are pale yellow and the luster is adamantine. The Mohs hardness is estimated at 2. The new mineral is brittle with irregular fracture and one perfect cleavage on {010}. The calculated density based on the ideal formula is 5.892 g/cm 3 . Chromschieffelinite is biaxial (-) with indices of refraction α = 1.930(5), β = 1.960(5), and γ = 1.975(5), measured in white light. The measured 2V is 68(2)°, the dispersion is strong, r &lt; v, and the optical orientation is X = b, Y = c, Z = a. No pleochroism was observed. Electron microprobe analysis provided: PbO 59.42, TeO 3  29.08, CrO 3  1.86, H 2 O 6.63 (structure), total 96.99 wt%; the empirical formula (based on 6 Te) is Pb 9.65 Te 6 O 19.96 (OH) 14.04 (CrO 4 ) 0.67 (H 2 O) 6.32 . The strongest powder X-ray diffraction lines are [d obs  in Å (hkl) I]: 9.814 (020) 100, 3.575 (042,202) 41, 3.347 (222) 44, 3.262 (241,060,113) 53, 3.052 (311) 45, 2.9455 (152,133) 55, 2.0396 (115,353) 33, and 1.6500 (multiple) 33. The crystal structures of schieffelinite (R 1  = 0.0282) and chromschieffelinite (R 1  = 0.0277) contain isolated Te 6+ O 6  octahedra and Te 2  6+ O 11  corner-sharing dimers, which are linked into a three-dimensional framework via bonds to Pb 2+  atoms. The framework has large channels along c, which contain disordered SO 4  or CrO 4  groups and H 2 O. The lone-electron pair of each Pb 2+  is stereochemically active, resulting in one-sided Pb-O coordination arrangements. The short Pb-O bonds of the Pb 2+  coordinations are all to Te 6+ O 6  octahedra, resulting in strongly bonded layers parallel to {010}, which accounts for the perfect {010} cleavage.

american mineralogist

Lead-tellurium oxysalts from Otto Mountain near Baker, California: VII. Chromschieffelinite, Pb 10 Te 6 O 20 (OH) 14 (CrO 4 )(H 2 O) 5 , the chromate analog of schieffelinite