The crystal structure of Ga-rich plumbogummite from Tsumeb, Namibia

S. J. Mills; A. R. Kampf; M. Raudsepp; A. G. Christy

doi:10.1180/minmag.2009.073.5.837

The crystal structure of Ga-rich plumbogummite from Tsumeb, Namibia

S. J. Mills, A. R. Kampf, M. Raudsepp, A. G. Christy

Research output: Contribution to journal › Article › peer-review

30 Citations (Scopus)

Abstract

Ga-rich plumbogummite, (Pb_0.87,Ca_0.13)_Σ1.00H(Al_1.95,Ga_1.05)_Σ3.00(PO₄)₂(OH)₆, from Tsumeb, Namibia, has rhombohedral symmetry, space group R3m, with the cell parameters a = 7.0752(19) Å, c = 16.818(4) Å and V = 729.1(3) Å³. The crystal structure has beenrefied to R₁ = 2.05%. Ga-rich plumbogummite has an alunite-type structure comprised of a rhombohedral stacking of (001) composite layers of corner-shared (Al,Ga)O₆ octahedra and PO₄ tetrahedra, with Pb atoms occupying icosahedrally coordinated sites between the layers. The Pb and H positions are discussed. Ga-rich plumbogummite is nonpleochroic, uniaxial (+), with indices of refraction, ε = 1.742(3) and ω = 1.722(3), determined in white light. The five strongest powder-diffraction lines [d in Å, (I/I_o), (hkl)] are: 2.995, (100), (113); 5.766, (95), (101); 2.236, (43), (107, 122); 3.539, (38), (110); 1.919 (32), (303, 033).

Original language	English
Pages (from-to)	837-845
Number of pages	9
Journal	Mineralogical Magazine
Volume	73
Issue number	5
DOIs	https://doi.org/10.1180/minmag.2009.073.5.837
Publication status	Published - Oct 2009

Access to Document

10.1180/minmag.2009.073.5.837

Cite this

@article{031c2cc2112f4433bdc332fe86a5c750,

title = "The crystal structure of Ga-rich plumbogummite from Tsumeb, Namibia",

abstract = "Ga-rich plumbogummite, (Pb0.87,Ca0.13)Σ1.00H(Al1.95,Ga1.05)Σ3.00(PO4)2(OH)6, from Tsumeb, Namibia, has rhombohedral symmetry, space group R3m, with the cell parameters a = 7.0752(19) {\AA}, c = 16.818(4) {\AA} and V = 729.1(3) {\AA}3. The crystal structure has beenrefied to R1 = 2.05%. Ga-rich plumbogummite has an alunite-type structure comprised of a rhombohedral stacking of (001) composite layers of corner-shared (Al,Ga)O6 octahedra and PO4 tetrahedra, with Pb atoms occupying icosahedrally coordinated sites between the layers. The Pb and H positions are discussed. Ga-rich plumbogummite is nonpleochroic, uniaxial (+), with indices of refraction, ε = 1.742(3) and ω = 1.722(3), determined in white light. The five strongest powder-diffraction lines [d in {\AA}, (I/Io), (hkl)] are: 2.995, (100), (113); 5.766, (95), (101); 2.236, (43), (107, 122); 3.539, (38), (110); 1.919 (32), (303, 033).",

keywords = "Bond valence, Crystal structure, Gallium, Kintoreite, Namibia, Plumbogummite, Tsumeb",

author = "Mills, {S. J.} and Kampf, {A. R.} and M. Raudsepp and Christy, {A. G.}",

year = "2009",

month = oct,

doi = "10.1180/minmag.2009.073.5.837",

language = "English",

volume = "73",

pages = "837--845",

journal = "Mineralogical Magazine",

issn = "0026-461X",

publisher = "Mineralogical Society",

number = "5",

}

TY - JOUR

T1 - The crystal structure of Ga-rich plumbogummite from Tsumeb, Namibia

AU - Mills, S. J.

AU - Kampf, A. R.

AU - Raudsepp, M.

AU - Christy, A. G.

PY - 2009/10

Y1 - 2009/10

N2 - Ga-rich plumbogummite, (Pb0.87,Ca0.13)Σ1.00H(Al1.95,Ga1.05)Σ3.00(PO4)2(OH)6, from Tsumeb, Namibia, has rhombohedral symmetry, space group R3m, with the cell parameters a = 7.0752(19) Å, c = 16.818(4) Å and V = 729.1(3) Å3. The crystal structure has beenrefied to R1 = 2.05%. Ga-rich plumbogummite has an alunite-type structure comprised of a rhombohedral stacking of (001) composite layers of corner-shared (Al,Ga)O6 octahedra and PO4 tetrahedra, with Pb atoms occupying icosahedrally coordinated sites between the layers. The Pb and H positions are discussed. Ga-rich plumbogummite is nonpleochroic, uniaxial (+), with indices of refraction, ε = 1.742(3) and ω = 1.722(3), determined in white light. The five strongest powder-diffraction lines [d in Å, (I/Io), (hkl)] are: 2.995, (100), (113); 5.766, (95), (101); 2.236, (43), (107, 122); 3.539, (38), (110); 1.919 (32), (303, 033).

AB - Ga-rich plumbogummite, (Pb0.87,Ca0.13)Σ1.00H(Al1.95,Ga1.05)Σ3.00(PO4)2(OH)6, from Tsumeb, Namibia, has rhombohedral symmetry, space group R3m, with the cell parameters a = 7.0752(19) Å, c = 16.818(4) Å and V = 729.1(3) Å3. The crystal structure has beenrefied to R1 = 2.05%. Ga-rich plumbogummite has an alunite-type structure comprised of a rhombohedral stacking of (001) composite layers of corner-shared (Al,Ga)O6 octahedra and PO4 tetrahedra, with Pb atoms occupying icosahedrally coordinated sites between the layers. The Pb and H positions are discussed. Ga-rich plumbogummite is nonpleochroic, uniaxial (+), with indices of refraction, ε = 1.742(3) and ω = 1.722(3), determined in white light. The five strongest powder-diffraction lines [d in Å, (I/Io), (hkl)] are: 2.995, (100), (113); 5.766, (95), (101); 2.236, (43), (107, 122); 3.539, (38), (110); 1.919 (32), (303, 033).

KW - Bond valence

KW - Crystal structure

KW - Gallium

KW - Kintoreite

KW - Namibia

KW - Plumbogummite

KW - Tsumeb

UR - http://www.scopus.com/inward/record.url?scp=71449091434&partnerID=8YFLogxK

U2 - 10.1180/minmag.2009.073.5.837

DO - 10.1180/minmag.2009.073.5.837

M3 - Article

SN - 0026-461X

VL - 73

SP - 837

EP - 845

JO - Mineralogical Magazine

JF - Mineralogical Magazine

IS - 5

ER -

The crystal structure of Ga-rich plumbogummite from Tsumeb, Namibia

Abstract

Access to Document

Other files and links

Fingerprint

Cite this