Synthesis and crystal structure of Ca(VO)2(PO4)2

Lii, Kwang Hwa; Chueh, B.R.; Kang, H. Y.; Wang, S.L.

doi:10.1016/0022-4596(92)90290-c

Cited by 28 publications

(16 citation statements)

References 10 publications

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“…These structures show that the formation of bonds is clearly the main driver of bond-length variation for this ion configuration, in addition to non-local bond-topological effects which create variability among the non-vanadyl bonds. However, in Ca(V 4+ O) 2 (PO 4 ) 2 (ICSD 72886;Lii et al, 1992), made up of corner-sharing dimers, the a priori (observed) bond valences are 4 Â 0.5 (0.464, 0.472, 0.502 and 0.513) and 2 Â 1 (0.388 and 1.624) v.u., with Á topol = 0.222 and Á cryst = 0.219 v.u. In this structure, the large value of Á topol results from non-local bond-topological asymmetry alone; however, the V 4+ ion moves off-centre in the direction of the strong bond, resulting in one much stronger and one much weaker bond than predicted.…”

Section: Mechanism (2): Ion Configurations Primarily Distorted Via Mumentioning

confidence: 99%

Bond-length distributions for ions bonded to oxygen: results for the transition metals and quantification of the factors underlying bond-length variation in inorganic solids

Gagné

Hawthorne

2020

IUCrJ

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Bond-length distributions are examined for 63 transition metal ions bonded to O2− in 147 configurations, for 7522 coordination polyhedra and 41 488 bond distances, providing baseline statistical knowledge of bond lengths for transition metals bonded to O2−. A priori bond valences are calculated for 140 crystal structures containing 266 coordination polyhedra for 85 transition metal ion configurations with anomalous bond-length distributions. Two new indices, Δtopol and Δcryst, are proposed to quantify bond-length variation arising from bond-topological and crystallographic effects in extended solids. Bond-topological mechanisms of bond-length variation are (1) non-local bond-topological asymmetry and (2) multiple-bond formation; crystallographic mechanisms are (3) electronic effects (with an inherent focus on coupled electronic vibrational degeneracy in this work) and (4) crystal-structure effects. The indices Δtopol and Δcryst allow one to determine the primary cause(s) of bond-length variation for individual coordination polyhedra and ion configurations, quantify the distorting power of cations via electronic effects (by subtracting the bond-topological contribution to bond-length variation), set expectation limits regarding the extent to which functional properties linked to bond-length variation may be optimized in a given crystal structure (and inform how optimization may be achieved) and more. These indices further provide an equal footing for comparing bond-length variation and the distorting power of ions across ligand types, including resolution for heteroligand polyhedra. The observation of multiple bonds is found to be primarily driven by the bond-topological requirements of crystal structures in solids. However, sometimes multiple bonds are observed to form as a result of electronic effects (e.g. the pseudo Jahn–Teller effect, PJTE); resolution of the origins of multiple-bond formation follows calculation of the Δtopol and Δcryst indices on a structure-by-structure basis. Non-local bond-topological asymmetry is the most common cause of bond-length variation in transition metal oxides and oxysalts, followed closely by the PJTE. Non-local bond-topological asymmetry is further suggested to be the most widespread cause of bond-length variation in the solid state, with no a priori limitations with regard to ion identity. Overall, bond-length variations resulting from the PJTE are slightly larger than those resulting from non-local bond-topological asymmetry, comparable with those resulting from the strong JTE, and less than those induced by π-bond formation. From a comparison of a priori and observed bond valences for ∼150 coordination polyhedra in which the strong JTE or the PJTE is the main reason underlying bond-length variation, the JTE is found not to have a cooperative relation with the bond-topological requirements of crystal structures. The magnitude of bond-length variation caused by the PJTE decreases in the following order for octahedrally coordinated d 0 transition metal oxyanions: Os8+ > Mo6+ > W6+ >> V5+ > Nb5+ > Ti4+ > Ta5+ > Hf4+ > Zr4+ > Re7+ >> Y3+ > Sc3+. Such ranking varies by coordination number; for [4] it is Re7+ > Ti4+ > V5+ > W6+ > Mo6+ > Cr6+ > Os8+ >> Mn7+; for [5] it is Os8+ > Re7+ > Mo6+ > Ti4+ > W6+ > V5+ > Nb5+. It is concluded that non-octahedral coordinations of d 0 ion configurations are likely to occur with bond-length variations that are similar in magnitude to their octahedral counterparts. However, smaller bond-length variations are expected from the PJTE for non-d 0 transition metal oxyanions.

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Section: Mechanism (2): Ion Configurations Primarily Distorted Via Mumentioning

confidence: 99%

Bond-length distributions for ions bonded to oxygen: results for the transition metals and quantification of the factors underlying bond-length variation in inorganic solids

Gagné

Hawthorne

2020

IUCrJ

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“…Complex vanadium phosphates Ca(VO) 2 (PO 4 ) 2 (Ref. 23) and Sr(VO) 2 (PO 4 ) 2 (Ref. 24) are isostructural and crystallize in a face-centered orthorhombic unit cell (space group F dd2, Z = 8).…”

Section: Crystal Structurementioning

confidence: 99%

Strong frustration due to competing ferromagnetic and antiferromagnetic interactions: Magnetic properties ofM(VO)2(PO4
Nath
¹
,
Tsirlin
²
,
Kaul
³

et al. 2008
Phys. Rev. B
42
1
31
0
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We present a detailed investigation of the magnetic properties of complex vanadium phosphates M(VO)2(PO4)2 (M = Ca and Sr) by means of magnetization, specific heat, 31 P NMR measurements, and band structure calculations. Experimental data evidence the presence of ferromagnetic and antiferromagnetic interactions in M(VO)2(PO4)2, resulting in a nearly vanishing Curie-Weiss temperature θCW ≤ 1 K that contrasts with the maximum of magnetic susceptibility at 3 K. Specific heat and NMR measurements also reveal weak exchange couplings with the thermodynamic energy scale Jc = 10 − 15 K. Additionally, the reduced maximum of the magnetic specific heat indicates strong frustration of the spin system. Band structure calculations show that the spin systems of the M(VO)2(PO4)2 compounds are essentially three-dimensional with the frustration caused by competing ferromagnetic and antiferromagnetic interactions. Both calcium and strontium compounds undergo antiferromagnetic long-range ordering at TN = 1.5 K and 1.9 K, respectively. The spin model reveals an unusual example of controllable frustration in three-dimensional magnetic systems.

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“…These structures show that the formation of π bonds is clearly the main driver of bond-length variation for this ion configuration, in addition to non-local bond-topological effects which create variability among the non-vanadyl bonds. However, in Ca(V 4+ O)2(PO4)2 (72886), 121 made up of corner-sharing dimers, the a priori (observed) bond valences are 4 × 0.5 (0.464, 0.472, 0.502 and 0.513) and 2 × 1 (0.388 and 1.624) v.u., with ∆ = 0.222 and ∆ = 0.219 v.u. In this structure, the large value of ∆ results from non-local bond-topological asymmetry alone; however, the V 4+ ion moves off-center in the direction of the strong bond, resulting in one much stronger, and one much weaker bond than predicted.…”

Section: Degenerate Electronic Statesmentioning

confidence: 99%

Bond-Length Distributions for Ions Bonded to Oxygen: Results for the Transition Metals and Quantification of the Factors Underlying Bond-Length Variation in Inorganic Solids

Gagné¹,

Hawthorne²

2020

Preprint

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Bond-length distributions are examined for 63 transition-metal ions bonded to O2- in 147 configurations, for 7522 coordination polyhedra and 41,488 bond distances, providing baseline statistical knowledge of bond lengths for transi-tion metals bonded to O2-. A priori bond valences are calculated for 140 crystal structures containing 266 coordination poly-hedra for 85 transition-metal ion configurations with anomalous bond-length distributions. Two new indices, Δ𝑡𝑜𝑝𝑜𝑙 and Δ𝑐𝑟𝑦𝑠𝑡, are proposed to quantify bond-length variation arising from bond-topological and crystallographic effects in extended solids. Bond-topological mechanisms of bond-length variation are [1] non-local bond-topological asymmetry, and [2] multi-ple-bond formation; crystallographic mechanisms are [3] electronic effects (with inherent focus on coupled electronic-vibra-tional degeneracy in this work), and [4] crystal-structure effects. The Δ𝑡𝑜𝑝𝑜𝑙 and Δ𝑐𝑟𝑦𝑠𝑡 indices allow one to determine the primary cause(s) of bond-length variation for individual coordination polyhedra and ion configurations, quantify the dis-torting power of cations via electronic effects (by subtracting the bond-topological contribution to bond-length variation), set expectation limits regarding the extent to which functional properties linked to bond-length variations may be optimized in a given crystal structure (and inform how optimization may be achieved), and more. We find the observation of multiple bonds to be primarily driven by the bond-topological requirements of crystal structures in solids. However, we sometimes observe multiple bonds to form as a result of electronic effects (e.g. the pseudo Jahn-Teller effect); resolution of the origins of multiple-bond formation follows calculation of the Δ𝑡𝑜𝑝𝑜𝑙 and Δ𝑐𝑟𝑦𝑠𝑡 indices on a structure-by-structure basis. Non-local bond-topological asymmetry is the most common cause of bond-length variation in transition-metal oxides and oxysalts, followed closely by the pseudo Jahn-Teller effect (PJTE). Non-local bond-topological asymmetry is further suggested to be the most widespread cause of bond-length variation in the solid state, with no a priori limitations with regard to ion identity. Overall, bond-length variations resulting from the PJTE are slightly larger than those resulting from non-local bond-topological asym-metry, comparable to those resulting from the strong JTE, and less than those induced by π-bond formation. From a compar-ison of a priori and observed bond valences for ~150 coordination polyhedra in which the strong JTE or the PJTE is the main reason underlying bond-length variation, the Jahn-Teller effect is found not to have a symbiotic relation with the bond-topo-logical requirements of crystal structures. The magnitude of bond-length variations caused by the PJTE decreases in the fol-lowing order for octahedrally coordinated d0 transition metals oxyanions: Os8+ > Mo6+ > W6+ >> V5+ > Nb5+ > Ti4+ > Ta5+ > Hf4+ > Zr4+ > Re7+ >> Y3+ > Sc3+. Such ranking varies by coordination number; for [4], it is Re7+ > Ti4+ > V5+ > W6+ > Mo6+ > Cr6+ > Os8+ >> Mn7+; for [5], it is Os8+ > Re7+ > Mo6+ > Ti4+ > W6+ > V5+ > Nb5+. We conclude that non-octahedral coordinations of d0 ion configurations are likely to occur with bond-length variations that are similar in magnitude to their octahedral counterparts. However, smaller bond-length variations are expected from the PJTE for non-d0 transition-metal oxyanions.<br>

show abstract

Synthesis and crystal structure of Ca(VO)2(PO4)2

Cited by 28 publications

References 10 publications

Bond-length distributions for ions bonded to oxygen: results for the transition metals and quantification of the factors underlying bond-length variation in inorganic solids

Bond-length distributions for ions bonded to oxygen: results for the transition metals and quantification of the factors underlying bond-length variation in inorganic solids

Strong frustration due to competing ferromagnetic and antiferromagnetic interactions: Magnetic properties ofM(VO)2(PO4
Nath
¹
,
Tsirlin
²
,
Kaul
³

et al. 2008
Phys. Rev. B
42
1
31
0
View full text Add to dashboard Cite

Bond-Length Distributions for Ions Bonded to Oxygen: Results for the Transition Metals and Quantification of the Factors Underlying Bond-Length Variation in Inorganic Solids

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Synthesis and crystal structure of Ca(VO)2(PO4)2

Cited by 28 publications

References 10 publications

Bond-length distributions for ions bonded to oxygen: results for the transition metals and quantification of the factors underlying bond-length variation in inorganic solids

Bond-length distributions for ions bonded to oxygen: results for the transition metals and quantification of the factors underlying bond-length variation in inorganic solids

Strong frustration due to competing ferromagnetic and antiferromagnetic interactions: Magnetic properties ofM(VO)2(PO4Nath1, Tsirlin2, Kaul3 et al. 2008Phys. Rev. B421310View full textAdd to dashboardCite

Bond-Length Distributions for Ions Bonded to Oxygen: Results for the Transition Metals and Quantification of the Factors Underlying Bond-Length Variation in Inorganic Solids

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Resources

About

Strong frustration due to competing ferromagnetic and antiferromagnetic interactions: Magnetic properties ofM(VO)2(PO4
Nath
¹
,
Tsirlin
²
,
Kaul
³

et al. 2008
Phys. Rev. B
42
1
31
0
View full text Add to dashboard Cite