ChemInform Abstract: Crystal Structure of Holmium Tetramolybdate, Ho2Mo4O15.

Abstract

The title compound is prepared by solid phase reaction of a stoichiometric mixture of Ho2O3 and MoO3, which is heated to 400‐650 °C for two weeks.

Subsolidus phase relations in the systems K2O–ZnO–AO3 (A=Mo, W)

“…Which consist of 11 three-phase regions, two ternary compounds and six binary compounds (K 2 MoO 4 , K 2 Mo 2 O 7 , K 2 Mo 3 O 10 , K 2 Mo 4 O 13 , ZnMoO 4 and Zn 3 Mo 2 O 9 ). In K 2 O-ZnO-MoO 3 pseudo-ternary system there exist two ternary compounds, K 4 Zn(MoO 4 ) 3 and K 2 Zn 2 (MoO 4 ) 3 under our sintered condition which is consistent with Efremov's report [16]. The compound K 4 Zn(MoO 4 ) 3 belongs to orthorhombic system with space group P2 1 2 1 2 1 .…”

“…The high temperature equilibrium between K 2 O-MoO 3 [11,12] and K 2 O-WO 3 [13][14][15] have been investigated. According to the reported phase diagram for the system K 2 MoO 4 -ZnMoO 4 [16], there are two ternary compounds, K 4 Zn(MoO 4 ) 3 and K 2 Zn 2 (MoO 4 ) 3 , melting incongruently at 615 • C and 610 • C, respectively. The eutectic relationship was found between K 4 Zn(MoO 4 ) 3 and K 2 Zn 2 (MoO 4 ) 3 at 530 • C. There is one ternary compound K 4 Zn(WO 4 ) 3 in the K 2 WO 4 -ZnWO 4 phase diagram [16], which melts incongruently at 635 • C. If eutectic exists between ZnO and these compounds, the ZnO single crystal could be grown at very low temperature.…”

“…According to the reported phase diagram for the system K 2 MoO 4 -ZnMoO 4 [16], there are two ternary compounds, K 4 Zn(MoO 4 ) 3 and K 2 Zn 2 (MoO 4 ) 3 , melting incongruently at 615 • C and 610 • C, respectively. The eutectic relationship was found between K 4 Zn(MoO 4 ) 3 and K 2 Zn 2 (MoO 4 ) 3 at 530 • C. There is one ternary compound K 4 Zn(WO 4 ) 3 in the K 2 WO 4 -ZnWO 4 phase diagram [16], which melts incongruently at 635 • C. If eutectic exists between ZnO and these compounds, the ZnO single crystal could be grown at very low temperature. So we have studied the phase relations of K 2 O-ZnO-AO 3 (A = Mo, W) systems in order to find suitable fluxes and growth regions for growing large and high quality ZnO single crystal at relative low temperature.…”

β-Nd2Mo4O15

“…Structures isotypic with -Nd 2 Mo 4 O 15 were reported for the Ce (Fallon & Gatehouse, 1982) and Pr (Efremov et al, 1988a) analogues. For the crystal structures, properties and applications of other molybdates with general formula RE 2 Mo 4 O 15 , see: RE = La (Dubois et al, 2001); Tb (Naruke & Yamase, 2001); La, Nd, Sm (Naruke & Yamase, 2003); Ho (Efremov et al, 1988b). (Borchardt & Bierstedt, 1966;Ouwerkerk et al, 1982 (Naruke & Yamase, 2001) and Ho 2 Mo 4 O 15 (Efremov et al, 1988b) with Z = 2, or triclinic Nd 2 Mo 4 O 15 (Naruke & Yamase, 2003) with Z = 3.…”

“…For the crystal structures, properties and applications of other molybdates with general formula RE 2 Mo 4 O 15 , see: RE = La (Dubois et al, 2001); Tb (Naruke & Yamase, 2001); La, Nd, Sm (Naruke & Yamase, 2003); Ho (Efremov et al, 1988b). (Borchardt & Bierstedt, 1966;Ouwerkerk et al, 1982 (Naruke & Yamase, 2001) and Ho 2 Mo 4 O 15 (Efremov et al, 1988b) with Z = 2, or triclinic Nd 2 Mo 4 O 15 (Naruke & Yamase, 2003) with Z = 3. In this paper, we present synthesis and crystal structure of the β-phase of compound Nd 2 Mo 4 O 15 which is structurally different from the first (α-) Nd 2 Mo 4 O 15 polymorph (Naruke & Yamase, 2003), but is isotypic with Ce 2 Mo 4 O 15 (Fallon & Gatehouse, 1982) and Pr 2 Mo 4 O 15 (Efremov et al, 1988a) with (Fig.…”