Cotunnite Mineral Data

General Cotunnite Information

Chemical Formula:

PbCl2

Composition:

Molecular Weight = 278.11 gm

Lead 74.50 % Pb 80.26 % PbO

Chlorine 25.50 % Cl 25.50 % Cl

- % Cl -5.75 % -O=Cl₂

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

PbCl₂

Environment:

Oxidized lead deposits.

IMA Status:

Valid Species (Pre-IMA) 1825

Locality:

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

Name Origin:

Named for Domenico Cotugno (Cotunnius) (1736-1822), Italian physician and Professor of Anatomy, University of Naples, Naples, Italy.

Synonym:

ICSD 27736

PDF 26-1150

Cotunnite Image

Images:

Cotunnite

Comments: White to tan translucent crystalline cotunnite on volcanic slag.
Location: Vesuvius, Campania, Italy. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Images:

Cotunnite Burnsite

Comments: Images of burnsite grains (dark) in intimate intergrowth with cotunnite (light). Images obtained by scanning electron microscopy.
Location: North Breach of the great fissure Tolbachik volcano eruption (1975-1976), Kamchatka Peninsula, Russia. Scale: Scale bar: 20 µ-m.
© Canadian Mineralogist

Cotunnite Crystallography

Axial Ratios:

a:b:c =0.8427:1:0.5013

Cell Dimensions:

a = 7.6222, b = 9.0448, c = 4.5348, Z = 4; V = 312.63 Den(Calc)= 5.91

Crystal System:

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

$Help on X Ray Diffraction:$ X Ray Diffraction:

By Intensity(I/I_o): 3.581(1), 3.89(0.73), 2.778(0.56),

Forms:

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Forms: ( 1 2 0) ( 0 1 0) ( 0 1 1) ( 1 1 1) ( 1 1 0) ( 1 0 0)

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Crystal Structure:

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Wyckoff R W G , Crystal Structures , 1 (1963) p.298-306, Second edition. Interscience Publishers, New York, New York

Physical Properties of Cotunnite

Cleavage:

{001} Perfect

Color:

Colorless, Green, Yellow, White.

Density:

5.3 - 5.8, Average = 5.55

Diaphaneity:

Transparent to translucent

Fracture:

Conchoidal - Uneven - Uneven fracture producing small, conchoidal fragments.

Habit:

Acicular - Occurs as needle-like crystals.

Habit:

Massive - Granular - Common texture observed in granite and other igneous rock.

Hardness:

1.5-2 - Talc-Gypsum

Luster:

Adamantine

Streak:

white

Optical Properties of Cotunnite

Gladstone-Dale:

CI meas= -0.179 (Poor) - where the CI = (1-KPDmeas/KC)
CI calc= -0.107 (Poor) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2073,KPDmeas= 0.2208,KC= 0.1873
Ncalc = 1.99 - 2.11

Optical Data:

Biaxial (+), a=2.199, b=2.217, g=2.26, bire=0.0610, 2V(Calc)=68, 2V(Meas)=67.2.

Calculated Properties of Cotunnite

Electron Density:

Bulk Density (Electron Density)=4.93 gm/cc
note: Specific Gravity of Cotunnite =5.91 gm/cc.

Fermion Index:

Fermion Index = 0.16
Boson Index = 0.84

Photoelectric:

PE_Cotunnite=1,372.93 barns/electron
U=PE_Cotunnite x rElectron Density=6,768.86 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Cotunnite is Not Radioactive

Cotunnite Classification

Dana Class:

09.02.07.01 (09)Anhydrous and Hydrated Halides

(09.02)where A (X)2

(09.02.07)Cotunnite Group

09.02.07.01 Cotunnite PbCl2 Pnam 2/m 2/m 2/m

09.02.07.02 Hydrophilite? CaCl2 Pnnm 2/m 2/m 2/m

09.02.07.03 Coccinite! HgI2(?) P 4₁/nmc 4/m 2/m 2/m

Strunz Class:

03.DC.85 03 - HALIDES

03.D - Oxyhalides, Hydroxyhalides and Related Double Halides

03.DC -With Pb (As,Sb,Bi), without Cu

03.DC.85 Cotunnite PbCl2 Pnam 2/m 2/m 2/m

Other Cotunnite Information

References:

NAME( AntBidBlaNic3) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Enc. of Minerals,2nd ed.,1990)

See Also:

Links to other databases for Cotunnite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - EUROmin Project
4 - Ecole des Mines de Paris
5 - GeoScienceWorld
6 - Google Images
7 - Google Scholar
8 - Handbook of Mineralogy (MinSocAm)
9 - Handbook of Mineralogy (UofA)
10 - MinDAT
11 - Mineralienatlas (Deutsch)
12 - Online Mineral Museum
13 - QUT Mineral Atlas
14 - Ruff.Info
15 - WWW-MINCRYST

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Ask about Cotunnite here :
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Print or Cut-and-Paste your Cotunnite Specimen Label here :

Cotunnite

PbCl2
Dana No: 09.02.07.01 Strunz No: 03.DC.85
Locality:

Notes: