Wiklundite

Wiklundite is a rare^[3] and complex arsenate arsenite-silicate mineral with the chemical formula Pb₂(Mn²⁺,Zn)₃(Fe³⁺,Mn²⁺)₂(Mn²⁺,Mg)₁₉(As³⁺O₃)₂(Si,As⁵⁺O₄)₆(OH)₁₈Cl₆. The mineral characterizes in a large c unit cell parameter.^[2] It was found in Långban, Sweden - a home for many rare and exotic minerals.^[4]

Wiklundite
General
Category	Silicate
Formula	Pb2(Mn2+,Zn)3(Fe3+,Mn2+)2(Mn2+,Mg)19(As3+O3)2(Si,As5+O4)6(OH)18Cl6
IMA symbol	Wik[1]
Crystal system	Trigonal
Crystal class	Hexagonal scalenohedral (3m) H-M symbol: (3 2/m)
Space group	R3c
Unit cell	a = 8.26, c = 126.59 [Å] (approximated)
Identification
References	[2]

Relation to other minerals

Structure of wiklundite is unique.^[2] A slightly chemically similar mineral, although lacking manganese and iron, is hereroite.^[5]