Red and Molybdate Orange

Molybdate red and molybdate orange [12656-85-8], C.I. Pigment Red 104 77605, are mixed-phase pigments with the general formula Pb(Cr,Mo,S)04 [3.131]. Most commercial products have a Mo03 content of 4-6 % (refractive index 2.3-2.65, density 5.4-6.3 g/cm3). Their hue depends on the proportion of molybdate, crystal form, and particle size. 

The colors of lead molybdate pigments vary from red with a yellow hue to red with a blue hue. Since chrome orange is no longer available (see Section 3.4.3), molybdate orange has become much more important. 

To give the lead molybdate pigments very good stability to fight, weathering, chemical attack, and temperature, the same methods are used as those for the stabilization of chrome yellow pigments (see Section 3.4.1) [3.134]-[3.142], 

Molybdate orange and molybdate red are mainly used in paints, coil coatings, and for coloring plastics (e.g., polyethylene, polyesters, polystyrene). The temperature-stable grades are the most suitable for coil coatings and plastics. 

Total world production of molybdate orange and molybdate red in 1996 was 13 000 t. 

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Lead chromate occurs in nature as crocoite, an orange-red mineral. Synthetically prepared lead chromate and its solid solutions with lead sulfate and lead molybdate represent a hue range from primrose yellow to red. The various hues of chrome yellow, chrome orange, and molybdate orange depend not only on composition but also on crystal structure and particle size. 

Molybdate orange and red are pigments (qv) that contain lead(II) molybdate [10190-33-3], PbMoO, formulated in mixed phases with PbCrO and PbSO. The mixed phase is more intensely colored than any of the component phases. Concerns about lead content are lessening the use of these materials (see also Paint). Various organic dyes are precipitated with heteropolymolybdates. This process allows the fixation of the dye in various fabrics. The molybdenum anion generally imparts light stabiHty to the colorant as weU (91). 

P.R.48 4, the manganese salt, affords red shades, which are noticeably on the bluish side of P.R.48 3 and yellower than P.R.48 2. The pigment is used in a variety of applications, especially in paints. In order to produce opaque shades of red, P.R.48 4 is frequently combined with Molybdate Orange. The pigment is considerably more lightfast and durable than other P.R.48 types, especially in full shades. 

The most important chromate pigments include the lead chromate (chrome yellow) and lead molybdate pigments (molybdate orange and molybdate red) whose colors range from light lemon yellow to reds with a blue hue. Chrome yellow,... 

Use of red iron oxide in plastics has increased as cadmium reds and lead molybdate oranges have been restricted in their use. In combination with the appropriate organic red toners, red iron oxide can be used to cover some of the same color space formerly occupied by cadmium- or molybdate-containing formulations. The red iron oxide component of the organic-inorganic approach also lowers the cost of the formulation, opacifies the formulation, and offers an increment of UV stability to the formulation. 

Molybdate oranges are solid solutions of lead chromate, lead molybdate, and lead sulfate and range in hue from yellow-shade orange to medium red. Chrome orange is PbCr04 PbO and varies in hue from yellow-shade to red-shade orange with particle size manipulation. 

SYNS CHROMIC ACID, LEAD and MOLYBDENUM SALT CHROMIC ACID LEAD SALT with LEAD MOLYBDATE C.I. PIGMENT RED 104 LEAD CHROMATE, SULPHATE and MOLYBDATE MOLYBDENUM-LEAD CHROMATE MOLYBDENUM ORANGE... 

Lead compounds were once widely used also for paints. They were in great demand because they covered surfaces well and were available in a number of vivid colors. Among these were lead chromate (yellow), lead molybdate (reddish-orange), lead(II) oxide (canary yellow), red lead oxide (Pb304 red), and white lead, a complex lead carbonate/lead hydroxide mixture. As with other lead compounds, however, the potential health hazards of the element have greatly reduced the availability of lead-based paints. 

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