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ErS2 is Cubic Laves structured and crystallizes in the cubic Fd-3m space group. The structure is three-dimensional. Er3+ is bonded in a 12-coordinate geometry to twelve equivalent S+1.50- atoms. All Er–S bond lengths are 3.22 Å. S+1.50- is bonded to six equivalent Er3+ and six equivalent S+1.50- atoms to form a mixture of edge, face, and corner-sharing SEr6S6 cuboctahedra. All S–S bond lengths are 2.75 Å.
Eu(ErS2)2 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. there are two inequivalent Er3+ sites. In the first Er3+ site, Er3+ is bonded to six S2- atoms to form a mixture of edge and corner-sharing ErS6 octahedra. The corner-sharing octahedra tilt angles range from 48–65°. There are a spread of Er–S bond distances ranging from 2.66–2.75 Å. In the second Er3+ site, Er3+ is bonded to six S2- atoms to form a mixture of edge and corner-sharing ErS6 octahedra. The corner-sharing octahedra tilt angles range from 48–65°. There are a spread of Er–S bond distances ranging from 2.69–2.74 Å. Eu2+ is bonded in a 8-coordinate geometry to eight S2- atoms. There are a spread of Eu–S bond distances ranging from 3.04–3.29 Å. There are four inequivalent S2- sites. In the first S2- site, S2- is bonded to three equivalent Er3+ and two equivalent Eu2+ atoms to form a mixture of distorted edge and corner-sharing SEu2Er3 square pyramids. In the second S2- site, S2- is bonded in a 5-coordinate geometry to three Er3+ and two equivalent Eu2+ atoms. In the third S2- site, S2- is bonded to three equivalent Er3+ and two equivalent Eu2+ atoms to form a mixture of distorted edge and corner-sharing SEu2Er3 trigonal bipyramids. In the fourth S2- site, S2- is bonded in a 5-coordinate geometry to three Er3+ and two equivalent Eu2+ atoms.
Eu(ErS2)2 crystallizes in the tetragonal I-42d space group. The structure is three-dimensional. Er3+ is bonded to eight equivalent S2- atoms to form distorted ErS8 hexagonal bipyramids that share corners with four equivalent ErS8 hexagonal bipyramids, corners with four equivalent EuS8 hexagonal bipyramids, edges with four equivalent ErS8 hexagonal bipyramids, faces with four equivalent ErS8 hexagonal bipyramids, and faces with four equivalent EuS8 hexagonal bipyramids. There are a spread of Er–S bond distances ranging from 2.73–3.05 Å. Eu2+ is bonded to eight equivalent S2- atoms to form distorted EuS8 hexagonal bipyramids that share corners with eight equivalent ErS8 hexagonal bipyramids, edges with four equivalent EuS8 hexagonal bipyramids, and faces with eight equivalent ErS8 hexagonal bipyramids. There are four shorter (2.88 Å) and four longer (3.05 Å) Eu–S bond lengths. S2- is bonded in a 6-coordinate geometry to four equivalent Er3+ and two equivalent Eu2+ atoms.
Yb(ErS2)2 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Yb2+ is bonded to seven S2- atoms to form distorted YbS7 pentagonal bipyramids that share corners with eight ErS6 octahedra, edges with five ErS6 octahedra, edges with two equivalent YbS7 pentagonal bipyramids, and faces with two equivalent YbS7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 13–68°. There are a spread of Yb–S bond distances ranging from 2.86–2.99 Å. There are two inequivalent Er3+ sites. In the first Er3+ site, Er3+ is bonded to six S2- atoms to form ErS6 octahedra that share corners with three equivalent ErS6 octahedra, corners with four equivalent YbS7 pentagonal bipyramids, edges with six ErS6 octahedra, and an edgeedge with one YbS7 pentagonal bipyramid. The corner-sharing octahedra tilt angles range from 52–60°. There are a spread of Er–S bond distances ranging from 2.69–2.79 Å. In the second Er3+ site, Er3+ is bonded to six S2- atoms to form ErS6 octahedra that share corners with three equivalent ErS6 octahedra, corners with four equivalent YbS7 pentagonal bipyramids, edges with four ErS6 octahedra, and edges with four equivalent YbS7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 52–60°. There are a spread of Er–S bond distances ranging from 2.69–2.76 Å. There are four inequivalent S2- sites. In the first S2- site, S2- is bonded to three equivalent Yb2+ and two equivalent Er3+ atoms to form a mixture of edge and corner-sharing SYb3Er2 square pyramids. In the second S2- site, S2- is bonded to two equivalent Yb2+ and three Er3+ atoms to form a mixture of distorted edge and corner-sharing SYb2Er3 trigonal bipyramids. In the third S2- site, S2- is bonded in a rectangular see-saw-like geometry to four Er3+ atoms. In the fourth S2- site, S2- is bonded to two equivalent Yb2+ and three Er3+ atoms to form SYb2Er3 square pyramids that share corners with two equivalent SYb3Er2 square pyramids, corners with two equivalent SYb2Er3 trigonal bipyramids, edges with five SYb2Er3 square pyramids, and edges with three equivalent SYb2Er3 trigonal bipyramids.
La(ErS2)3 crystallizes in the monoclinic P2_1/m space group. The structure is three-dimensional. there are three inequivalent Er3+ sites. In the first Er3+ site, Er3+ is bonded to seven S2- atoms to form distorted ErS7 pentagonal bipyramids that share corners with three ErS6 octahedra, edges with two equivalent ErS6 octahedra, and edges with four equivalent ErS7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 38–51°. There are a spread of Er–S bond distances ranging from 2.69–2.91 Å. In the second Er3+ site, Er3+ is bonded to six S2- atoms to form ErS6 octahedra that share corners with three equivalent ErS6 octahedra, a cornercorner with one ErS7 pentagonal bipyramid, edges with four equivalent ErS6 octahedra, and edges with two equivalent ErS7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 54–62°. There are a spread of Er–S bond distances ranging from 2.67–2.77 Å. In the third Er3+ site, Er3+ is bonded to six S2- atoms to form ErS6 octahedra that share corners with three equivalent ErS6 octahedra, corners with two equivalent ErS7 pentagonal bipyramids, and edges with four equivalent ErS6 octahedra. The corner-sharing octahedra tilt angles range from 54–62°. There are a spread of Er–S bond distances ranging from 2.65–2.79 Å. La3+ is bonded in a 8-coordinate geometry to eight S2- atoms. There are a spread of La–S bond distances ranging from 2.94–3.07 Å. There are six inequivalent S2- sites. In the first S2- site, S2- is bonded in a distorted rectangular see-saw-like geometry to four Er3+ atoms. In the second S2- site, S2- is bonded to three Er3+ and one La3+ atom to form distorted SLaEr3 trigonal pyramids that share corners with two equivalent SLa2Er3 square pyramids, corners with four SLa3Er2 trigonal bipyramids, corners with two equivalent SLaEr3 trigonal pyramids, edges with three equivalent SLa2Er3 square pyramids, and edges with two equivalent SLa3Er2 trigonal bipyramids. In the third S2- site, S2- is bonded in a 4-coordinate geometry to four Er3+ atoms. In the fourth S2- site, S2- is bonded to two equivalent Er3+ and three equivalent La3+ atoms to form distorted SLa3Er2 trigonal bipyramids that share corners with four equivalent SLa2Er3 square pyramids, corners with two equivalent SLa2Er3 trigonal bipyramids, a cornercorner with one SLaEr3 trigonal pyramid, an edgeedge with one SLa2Er3 square pyramid, edges with seven SLa3Er2 trigonal bipyramids, and edges with two equivalent SLaEr3 trigonal pyramids. In the fifth S2- site, S2- is bonded to three Er3+ and two equivalent La3+ atoms to form distorted SLa2Er3 trigonal bipyramids that share corners with two equivalent SLa2Er3 square pyramids, corners with two equivalent SLa3Er2 trigonal bipyramids, corners with three equivalent SLaEr3 trigonal pyramids, an edgeedge with one SLa2Er3 square pyramid, and edges with five SLa3Er2 trigonal bipyramids. In the sixth S2- site, S2- is bonded to three equivalent Er3+ and two equivalent La3+ atoms to form distorted SLa2Er3 square pyramids that share corners with six SLa2Er3 trigonal bipyramids, corners with two equivalent SLaEr3 trigonal pyramids, edges with four equivalent SLa2Er3 square pyramids, edges with two SLa2Er3 trigonal bipyramids, and edges with three equivalent SLaEr3 trigonal pyramids.
ErS2 crystallizes in the tetragonal P4/nmm space group. The structure is three-dimensional. Er3+ is bonded in a 9-coordinate geometry to nine S+1.50- atoms. There are five shorter (2.81 Å) and four longer (2.88 Å) Er–S bond lengths. There are two inequivalent S+1.50- sites. In the first S+1.50- site, S+1.50- is bonded to five equivalent Er3+ atoms to form a mixture of distorted corner and edge-sharing SEr5 trigonal bipyramids. In the second S+1.50- site, S+1.50- is bonded in a 8-coordinate geometry to four equivalent Er3+ and four equivalent S+1.50- atoms. All S–S bond lengths are 2.71 Å.
Er3SmS6 crystallizes in the monoclinic P2_1/m space group. The structure is three-dimensional. there are three inequivalent Er3+ sites. In the first Er3+ site, Er3+ is bonded to six S2- atoms to form ErS6 octahedra that share corners with three equivalent ErS6 octahedra, corners with two equivalent ErS7 pentagonal bipyramids, and edges with four equivalent ErS6 octahedra. The corner-sharing octahedra tilt angles range from 56–61°. There are a spread of Er–S bond distances ranging from 2.64–2.77 Å. In the second Er3+ site, Er3+ is bonded to seven S2- atoms to form distorted ErS7 pentagonal bipyramids that share corners with three ErS6 octahedra, edges with two equivalent ErS6 octahedra, and edges with four equivalent ErS7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 38–51°. There are a spread of Er–S bond distances ranging from 2.67–2.91 Å. In the third Er3+ site, Er3+ is bonded to six S2- atoms to form ErS6 octahedra that share corners with three equivalent ErS6 octahedra, a cornercorner with one ErS7 pentagonal bipyramid, edges with four equivalent ErS6 octahedra, and edges with two equivalent ErS7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 56–61°. There are a spread of Er–S bond distances ranging from 2.65–2.76 Å. Sm3+ is bonded in a 8-coordinate geometry to eight S2- atoms. There are a spread of Sm–S bond distances ranging from 2.86–3.02 Å. There are six inequivalent S2- sites. In the first S2- site, S2- is bonded to three Er3+ and one Sm3+ atom to form distorted SSmEr3 trigonal pyramids that share corners with two equivalent SSm2Er3 square pyramids, corners with four SSm3Er2 trigonal bipyramids, corners with two equivalent SSmEr3 trigonal pyramids, edges with three equivalent SSm2Er3 square pyramids, and edges with two equivalent SSm3Er2 trigonal bipyramids. In the second S2- site, S2- is bonded to three equivalent Er3+ and two equivalent Sm3+ atoms to form distorted SSm2Er3 square pyramids that share corners with six SSm2Er3 trigonal bipyramids, corners with two equivalent SSmEr3 trigonal pyramids, edges with four equivalent SSm2Er3 square pyramids, edges with two SSm2Er3 trigonal bipyramids, and edges with three equivalent SSmEr3 trigonal pyramids. In the third S2- site, S2- is bonded to two equivalent Er3+ and three equivalent Sm3+ atoms to form distorted SSm3Er2 trigonal bipyramids that share corners with four equivalent SSm2Er3 square pyramids, corners with two equivalent SSm2Er3 trigonal bipyramids, a cornercorner with one SSmEr3 trigonal pyramid, an edgeedge with one SSm2Er3 square pyramid, edges with seven SSm3Er2 trigonal bipyramids, and edges with two equivalent SSmEr3 trigonal pyramids. In the fourth S2- site, S2- is bonded in a 4-coordinate geometry to four Er3+ atoms. In the fifth S2- site, S2- is bonded in a rectangular see-saw-like geometry to four Er3+ atoms. In the sixth S2- site, S2- is bonded to three Er3+ and two equivalent Sm3+ atoms to form distorted SSm2Er3 trigonal bipyramids that share corners with two equivalent SSm2Er3 square pyramids, corners with two equivalent SSm3Er2 trigonal bipyramids, corners with three equivalent SSmEr3 trigonal pyramids, an edgeedge with one SSm2Er3 square pyramid, and edges with five SSm3Er2 trigonal bipyramids.
ERS2 radar data acquired before and after the Mw7.6, Manyi (Tibet) earthquake of November 8, 1997, provide geodetic information about the surface displacement produced by the earthquake in two ways. (1) The sub-pixel geometric adjustment of the before and after images provides a two dimensional offset field with a resolution of approx, 1m in both the range (radar line of sight) and azimuth (satellite track) directions. Comparison of offsets in azimuth and range indicates that the displacement along the fault is essentially strike-slip and in a left-lateral sense. The offset map reveals a relatively smooth and straight, N78E surface rupture that exceeds 150 km in length, consistent with the EW plane of the Harvard CMT solution. The rupture follows the trace of a quaternary fault visible on satellite imagery (Tapponnier and Molnar, 1978; Wan Der Woerd, pers. comm.). (2) Interferometric processing of the SAR data provides a range displacement map with a precision of a few millimeters. The slip distribution along the rupture reconstructed from the range change map is a bell-shaped curve in the 100-km long central section of the fault with smaller, local maxima near both ends. The curve shows that the fault slip exceeds 2.2 m in range, or 6.2 in strike-slip, along a 30-km long section of the fault and remains above 1 m in range, approx. 3 m strike-slip, along most of its length. Preliminary forward modeling of the central section of the rupture, assuming a uniform slip distribution with depth, indicates that the slip occur-red essentially between 0 and the depth of 10 km, consistent with a relatively shallow event (Velasco et al., 1998).