Pseudocotunnite Mineral Data

Pseudocotunnite Mineral Data +

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General Pseudocotunnite Information

Chemical Formula:

K2PbCl4 (?)

Composition:

Molecular Weight = 427.21 gm

Potassium 18.30 % K 22.05 % K₂O

Lead 48.50 % Pb 52.25 % PbO

Chlorine 33.19 % Cl 33.19 % Cl

- % Cl -7.49 % -O=Cl₂

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

K₂PbCl₄

Environment:

In fumaroles, associated with cotunnite.

IMA Status:

Valid Species (Pre-IMA) 1873

Locality:

Vesuvius, Italy. Link to MinDat.org Location Data.

Name Origin:

Named for the Greek "pseudo", false and cotunnite, a mineral it resembles in some respects.

Pseudocotunnite Image

Images:

Pseudocotunnite

Comments: Bright white botryoidal pseudocotunnite coatings.
Location: Vesuvius, Campania, Italy. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Pseudocotunnite Crystallography

Axial Ratios:

a:b:c =0.8322:1:0.4889

Cell Dimensions:

a = 9.82, b = 11.8, c = 5.77, Z = 4; V = 668.60 Den(Calc)= 4.24

Crystal System:

Orthorhombic - DipyramidalH-M Symbol (2/m 2/m 2/m) Space Group: P nma

Physical Properties of Pseudocotunnite

Color:

Colorless, Green yellow, Yellow, White.

Density:

4.25

Diaphaniety:

Transparent to Translucent

Habit:

Acicular - Occurs as needle-like crystals.

Habit:

Aggregates - Made of numerous individual crystals or clusters.

Habit:

Platy - Sheet forms (e.g. micas).

Luster:

Earthy (Dull)

Streak:

white

Optical Properties of Pseudocotunnite

Gladstone-Dale:

CI meas= -0.081 (Poor) - where the CI = (1-KPDmeas/KC)
CI calc= -0.084 (Poor) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2358,KPDmeas= 0.2353,KC= 0.2176

Optical Data:

Biaxial (?), b=2

Calculated Properties of Pseudocotunnite

Electron Density:

r_electron=3.74 gm/cc
note: r_{Pseudocotunnite}=4.25 gm/cc.

Fermion Index

Fermion Index = 0.1072
Boson Index = 0.8928

Photoelectric:

PE_{Pseudocotunnite}= 850.37 barns/electron
U=PE_{Pseudocotunnite} x r_electron=3,180.88 barns/cc.

Radioactivity:

GRapi = 232.44 (Gamma Ray American Petroleum Institute Units)

Estimated Radioactivity from Pseudocotunnite - barely detectable

Pseudocotunnite Classification

Dana Class:

11.2.1.1 (11)Halide Complexes; Alumino-fluorides

(11.2)where (A)m B (X)4

(11.2.1)Dana Group

11.2.1.1 Pseudocotunnite K2PbCl4(?) P nma 2/m 2/m 2/m

Strunz Class:

III/D.10-50 III - Halogenides

III/D - Oxi-halogenides with Pb - Bi - Sb and related compounds

III/D.10 - Cotunnite - Matlockite series

III/D.10-10 Fiedlerite Pb3Cl4F(OH)2 P1 1

III/D.10-20 Paralaurionite PbCl(OH) C 2/m 2/m

III/D.10-30 Laurionite PbCl(OH) Pnam 2/m 2/m 2/m

III/D.10-40 Cotunnite PbCl2 Pnam 2/m 2/m 2/m

III/D.10-50 Pseudocotunnite K2PbCl4(?) P nma 2/m 2/m 2/m

III/D.10-60 Matlockite PbFCl P 4/nmm 4/m 2/m 2/m

III/D.10-65 Rorisite (Ca,Mg)FCl P 4/nmm 4/m 2/m 2/m

III/D.10-70 Zavaritskite BiOF P 4/nmm 4/m 2/m 2/m

III/D.10-80 Bismoclite BiOCl P 4/nmm 4/m 2/m 2/m

III/D.10-90 Daubreeite BiO(OH,Cl) P 4/nmm 4/m 2/m 2/m

III/D.10-140 Symesite! Pb10(SO4)O7Cl4·(H2O) B1 1

Other Pseudocotunnite Information

References:

NAME( Dana8) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Dana8)

See Also:

Links to other databases for Pseudocotunnite :
1 -Am. Min. Crystal Structure Database 2 -Athena 3 - EUROmin Project 4 -Google Images 5 -Google Scholar 6 -Handbook of Mineralogy (UofA) 7 -MinDAT 8 -MinMax(Deutsch) 9 -MinMax(English) 10 -Mineralienatlas (Deutsch) 11 -QUT Mineral Atlas 12 -École des Mines de Paris

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Print or Cut-and-Paste your Pseudocotunnite Specimen Label here :

Pseudocotunnite

K2PbCl4 (?)
Dana No: 11.2.1.1 Strunz No: III/D.10-50
Locality:

Notes: