TY - JOUR

T1 - Wrightite, K2Al2O(AsO4)2, a new oxo-orthoarsenate from the Second scoria cone, Northern Breakthrough, Great Fissure eruption, Tolbachik volcano, Kamchatka peninsula, Russia

AU - Shablinskii, Andrey P.

AU - Filatov, Stanislav K.

AU - Vergasova, Lidyua P.

AU - Avdontseva, Eugeniya Yu

AU - Moskaleva, Svetlana V.

PY - 2018/12/1

Y1 - 2018/12/1

N2 - The new mineral wrightite, K2Al2O(AsO4)2, was found in 1983 at a fumarole on the Second scoria cone, Northern Breakthrough, Great Fissure eruption, Tolbachik volcano, Kamchatka peninsula, Russia, where it occurs as light yellow aggregates of transparent tabular crystals, with an average size of 0.05 mm × 0.03 mm × 0.005 mm. Wrightite is orthorhombic, space group Pnma, with the unit-cell parameters a = 8.230(5), b = 5.555(4), c = 17.584(1) Å, V = 803.9(6) Å3 and Z = 4 (from powder data). The empirical formula is (K1.69Na0.38)Σ2.07(Al1.80Fe0.24)Σ2.04As1.96O9. The crystal structure (R1 = 0.043) consists of Al2O(AsO4)2 layers in the ab plane with clusters of edge-sharing AlO6 octahedra. Each layer contains two independent isolated AsO4 tetrahedra and two AlO6 octahedra. AlO6 octahedra are linked by edges, forming zigzag chains along the b axis inside the Al-As layer. Eight- and six-coordinated K atoms are located in the interlayer space between Al2O(AsO4)2 layers. The mineral is biaxial (-), α =1.679(2), β =1.685(2), γ (calc.) =1.687; 2V(meas.) = 62(10)° (λ = 589 nm). The strongest lines in the powder X-ray diffraction pattern [d,Å(I)(hkl)] are: 8.77(36)(002); 4.458(17)(111); 4.010(19)(201,013); 3.875(19)(104) and 2.972(100)(015). The mineral was named in honour of Adrian Carl Wright, Emeritus Professor at the University of Reading, UK.

AB - The new mineral wrightite, K2Al2O(AsO4)2, was found in 1983 at a fumarole on the Second scoria cone, Northern Breakthrough, Great Fissure eruption, Tolbachik volcano, Kamchatka peninsula, Russia, where it occurs as light yellow aggregates of transparent tabular crystals, with an average size of 0.05 mm × 0.03 mm × 0.005 mm. Wrightite is orthorhombic, space group Pnma, with the unit-cell parameters a = 8.230(5), b = 5.555(4), c = 17.584(1) Å, V = 803.9(6) Å3 and Z = 4 (from powder data). The empirical formula is (K1.69Na0.38)Σ2.07(Al1.80Fe0.24)Σ2.04As1.96O9. The crystal structure (R1 = 0.043) consists of Al2O(AsO4)2 layers in the ab plane with clusters of edge-sharing AlO6 octahedra. Each layer contains two independent isolated AsO4 tetrahedra and two AlO6 octahedra. AlO6 octahedra are linked by edges, forming zigzag chains along the b axis inside the Al-As layer. Eight- and six-coordinated K atoms are located in the interlayer space between Al2O(AsO4)2 layers. The mineral is biaxial (-), α =1.679(2), β =1.685(2), γ (calc.) =1.687; 2V(meas.) = 62(10)° (λ = 589 nm). The strongest lines in the powder X-ray diffraction pattern [d,Å(I)(hkl)] are: 8.77(36)(002); 4.458(17)(111); 4.010(19)(201,013); 3.875(19)(104) and 2.972(100)(015). The mineral was named in honour of Adrian Carl Wright, Emeritus Professor at the University of Reading, UK.

KW - crystal structure

KW - fumarole minerals

KW - Kamchatka peninsula

KW - new mineral species

KW - oxo-orthoarsenate

KW - wrightite

UR - http://www.scopus.com/inward/record.url?scp=85060795126&partnerID=8YFLogxK

U2 - 10.1180/minmag.2017.081.091

DO - 10.1180/minmag.2017.081.091

M3 - Article

AN - SCOPUS:85060795126

VL - 82

SP - 1243

EP - 1251

JO - Mineralogical Magazine

JF - Mineralogical Magazine

SN - 0026-461X

IS - 6

ER -