Substituted tin niobium pyrochlore and tin niobium oxide pigments

1. An inorganic pigment comprising tin; a divalent metal; niobium; and an oxysulfide, an oxyselenide, or oxysulfo-selenide; wherein the pigment has the empirical formula:

M 2 Nb 2 Z 7 .XMNb 2 Z 6 or MNb 2 Z 6

where M comprises tin and a divalent metal; Z comprises oxygen and either sulfur, selenium, or a mixture of sulfur and selenium; and X ranges from 0 to 100.

2. The pigment of claim 1 , wherein M comprises Sn and Zn.

3. The pigment of claim 2 , wherein X is 0.

4. The pigment of claim 2 , wherein X is 0 and Z comprises sulfur and oxygen so that the ZnS:SnO ratio is between 0.04:1.96 and 0.20:1.80.

5. The pigment of claim 1 , wherein M additionally comprises at least one alkali earth metal.

6. The pigment of claim 1 , wherein M additionally comprises at least one transition metal.

7. The pigment of claim 1 , wherein the pigment has a pyrochlore structure.

8. The pigment of claim 1 , wherein the pigment has a foordite structure.

9. The pigment of claim 1 with the empirical formula:

MNb 2 Z 6

where M comprises tin and a divalent metal; and Z comprises oxygen and either sulfur, selenium, or a mixture of sulfur and selenium.

10. The pigment of claim 9 , wherein M comprises Sn and Zn.

11. The pigment of claim 1 , wherein the color of an acrylic masstone of the pigment has an L* of about 73.7 to about 82.8, an a* of about 4.9 to about 21.1, and a b* of about 72 to about 84.7.

12. The pigment of claim 1 , wherein the color of an acrylic masstone of the pigment has an L* of about 77.1 to about 78.4, an a* of about 8.0 to about 16.5, and a b* of about 76.6 to about 79.5.

13. The pigment of claim 1 , wherein the color of an acrylic masstone of the pigment has an L* of about 77.1 to about 78, an a* of about 8.0 to about 16.5, and a b* of about 76.6 to about 78.8.

14. The pigment of claim 1 , characterized by an X-ray powder diffraction pattern comprising d-spacings of about 3.095 Å, 3.056 Å, 2.841 Å, 2.645 Å, 1.871 Å, 1.677 Å, and 1.596 Å.

15. The pigment of claim 1 , characterized by an X-ray powder diffraction pattern comprising d-spacings of about 3.584 Å, 3.066 Å, 2.836 Å, 2.779 Å, 2.434 Å, and 1.910 Å.

16. The pigment of claim 1 , characterized by an X-ray powder diffraction pattern comprising d-spacings of about 3.056 Å, 2.647 Å, 1.872 Å, and 1.596 Å.

17. The pigment of claim 1 , having an infrared reflectance, as measured on compressed dry powders using an integrating sphere instrument, in accordance with ASTM E903-96, of greater than 70% on average throughout the region from 700 nm to 2500 nm.